As the final exam in the COMLEX series, it’s no surprise that the COMLEX Level 3 is an extremely challenging and diverse assessment. The wholly multiple-choice question (MCQ) format of the Levels 1 and 2-CE is now expanded to include both extended MCQ and short answer questions, and the range and depth of domains tested is truly staggering. But since you’ve now passed the previous COMLEX exams, made it through your residency interview and are now acclimating to life as an Intern , you should have a pretty solid grounding for the Level 3 that can simply be improved upon and sharpened for the big day. In this guide, we’ll help you understand the scope of the Level 3 and provide preparation and study tips to help you head into it with confidence.

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Article Contents
14 min read

What is the COMLEX Level 3? What’s On the COMLEX Level 3? COMLEX Level 3: Two Distinct Dimensions Scoring Registration and Accommodation Preparation for the COMLEX Level 3 What to Expect on Exam Day Study Tips Conclusion FAQ

What is the COMLEX Level 3?

The COMLEX Level 3 is the final exam in a series of 4 comprehensive licensing exams administered by the National Board of Osteopathic Medicine Examiners (NBOME). The 4 exams of the COMLEX are structured into 3 parts and 4 exams total:

Two-day computer-based, application of osteopathic medical knowledge concepts related to clinical sciences, patient safety and independent practice, foundational competency domains and clinical presentations

Candidates take the COMLEX Level 3 after graduating from their DO schools, usually before the end of their Intern/first year of residency. Like the Level 1 and 2-CE exams, the COMLEX Level 3 is taken at a Prometric computer testing center, and is comprised of a series of multiple choice questions. However, the Level 3 also adds two additional question types, the “extended” MCQ which may have multiple correct responses, and a section of short essay questions. This is reflective of the wider scope of tested information and maturity of the student taking the exam. The Level 3 is not an exam for a 2nd year DO student, meant to assess their foundational biomedical knowledge—rather, it is the final assessment of a new doctor’s clinical decision-making skills before licensure and certification enabling them to operate independently as an Osteopathic generalist. Of course, since this happens before the end of their residency program, you can think of the Level 3 as more of an epilogue or capstone to DO school, rather than the very last hurdle before fully independent practice.

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What’s On the COMLEX Level 3?

As noted, the COMLEX Level 3 is taken by DO graduates undertaking specialty training in a residency program. As such, its focus is far less academic and much more on Osteopathic practice and clinical skills. The questions on the Level 3 assess competency in the 8 foundational clinical disciplines, which are:

Question Structure

The COMLEX Level 3 is comprised of 420 MCQs including 26 Clinical Decision-Making (CDM) cases with 2-4 questions each. While the bulk of the MCQs use the standard single-answer structure, the CDM questions are either extended multiple choice or short answer/constructed response—a structure similar to the CDM questions on the MCCQE Part 1 exam taken by Canadian medical students. Testing is broken into four 3.5-hour testing sessions spread over two days, with two sessions each day.

As with all other COMLEX exams save the Level 2-PE, the COMLEX Level 3 is structured around two distinct dimensions of osteopathic proficiency.

COMLEX Level 3: Two Distinct Dimensions

Similar to the Level 1 and 2-CE, the types of clinical problem-solving involved in the COMLEX Level 3 exam are organized around two dimensions: Competency Domains and Clinical Presentations. Both dimensions integrate five central aspects of osteopathic medical care:

Dimension 1: Competency Domains

Dimension 1 in the Level 3 exam is noticeably different in its proportions than the two preceding MCQ-based COMLEX exams:

Osteopathic Principles, Practice, and Manipulative Treatment — 10%

Osteopathic Patient Care and Procedural Skills — 40%

Application of Knowledge for Osteopathic Medical Practice — 17%

Foundational Biomedical Sciences base —10% of the Application of Knowledge for Osteopathic Medical Practice section (a mere 1.7% of the overall test)

Practice-Based Learning and Improvement in Osteopathic Medical Practice — 8%

Interpersonal and Communication Skills in the Practice of Osteopathic Medicine — 3%

Professionalism in the Practice of Osteopathic Medicine — 6%

Systems-Based Practice in Osteopathic Medicine — 6%

Dimension 2: Clinical Presentations

Dimension 2 focuses on Clinical Presentations that represent the ways in which a particular patient or community presents for Osteopathic Medical Care. Similar to Dimension 1, each category of Clinical Presentation makes up a specific minimum percentage of questions. They are:

The distribution of questions on each of these two dimensions is slightly more structured than on previous exams, in part due to the addition of the CDM case format. The NBOME’s outline for the 2-day testing period is as follows:

Day 1

Day 2

Although the NBOME doesn’t say this explicitly, test-takers can expect a heavier focus on Dimension 2 in the CDM questions, although the comprehensive nature of the section means virtually all components of each dimension will be tested. Besides the CDM section’s use of extended MCQs and short answers, the basic structure of the exam should be extremely familiar to test-takers by this point, as it does mostly follow the format of the Level 1 and Level 2-CE. Nonetheless, the sheer volume and duration of the COMLEX Level 3 means that it will feel quite a bit different. 

Clinical Decision-Making Questions

It’s worth a moment to discuss how unique the CDM section is in the overall COMLEX roadmap. Previously, all MCQs were single-answer, and the Level 2-PE a purely performance-based exam without any MCQs. The Clinical Decision-Making portion still relies on case studies of patient presentations, but, in line with the sophistication of the now Intern doctor’s clinical duties, the answers will be much less linear or binary.

CDM cases assess the ability to perform as an independent physician, and so test not only factual knowledge but the ability to apply this knowledge to care for patients. As the NBOME notes, the Level 3 is the pathway to licensure, and so this section is far more demanding than those comprised of single-answer MCQs. Specifically, the cases covered in the CDM sections focus on critical decisions regarding patient care and treatment—a context that in reality is far from simple and “single answer” in most situations. These questions require extensive knowledge in data acquisition practices like obtaining patient histories, physical exam findings, and ordering tests. Additionally, CDM questions test data interpretation skills and treatment as well, significantly extending the scope of the patient presentation question model used in previous COMLEX exams. 

We’ll get into prep strategies in a moment but, as you can probably suspect at this point, the CDM sections are what most test-takers fear the most. This doesn’t need to be the case though—as with the Level 2-PE, the COMLEX Level 3’s CDM questions are in a sense merely story problems of situations you’ll have acquired at least some experience in during your 3rd and 4th year clinical rotations, and provided you’ve kept good notes and received quality, detailed feedback from your attending physicians during these years, not much should feel totally new or unfamiliar. 


Scores on the COMLEX Level 3 utilize a converted 3-digit standard score, ranging from 9-999, with a mean of 520. The minimum score to pass the exam is a 350. Lastly, it’s important to note that since the COMLEX Level 3 is taken after graduation from DO school, the numerical score used to establish passing or failing the exam is effectively meaningless. Passing is the only thing that matters, as a more detailed score would not be used in consideration by competitive residency programs for admission.

A quick recap of all 4 COMLEX exams:


Registration and Accommodation  

Candidates become eligible to register for the COMLEX Level 3 when they’ve satisfied four requirements:

  • Passed COMLEX Levels 1, 2-CE, and 2-PE
  • Graduated from an accredited College of Osteopathic Medicine (COM)
  • Earned a DO degree
  • Received attestation by a residency program director or COM Dean that they’re in good academic and professional standing

Since you’ll have already registered in the NBOME Client Registration System (CRS) back in year 1 for the COMLEX Level 1, registering for the Level 3 is fairly simple. Once you’ve made sure your name and other important information in the NBOME CRS is correct, you need only confirm your eligibility and then register for the testing date you desire. Additionally, if you want to change the date of an existing exam appointment, you can do so through this CRS portal. 

NBOME provides reasonable and appropriate additional accommodations for test-takers in accordance with the Americans with Disabilities Act. Students requiring accommodation on test day should submit a Request for Test Accommodations via the process elaborated on the NBOME’s test accommodations page at least 75 days ahead of their test date. However, such requests may require additional documentation, so we recommend that you submit this form, if necessary, as far ahead of your test date as possible to account for any back-and-forth in sorting out details. Additionally, Prometric offers an extensive array of available accommodations, from sign language interpreters to specialized computer peripherals.

Scheduling your exam may be trickier for the Level 3 since you’ll be busy with the first year figuring out how to be a resident doctor. Fortunately, you can schedule your exam for whenever you’d like, and most candidates plan their test date at least 3-6 months ahead of time. This is important for providing ample time to create your study plan, but also so you can ensure that your test date will fall in a slightly easier period of your intern year. For instance, many candidates choose to take the COMLEX Level 3 during an outpatient or consult block, which is easier for your program to accommodate. However, many people argue that it’s best to take the Level 3 as early as possible in your Internship year, when much of the core rotation skills/material of your final 2 years of DO school will be freshest in your mind. Especially if you’re choosing a medical specialty that’s highly specialized, such as surgery or urology, there’s a higher risk of forgetting details from the “basic” clinical disciplines like OB/GYN and Internal Medicine as your Intern year progresses. There’s no one right way on this matter, and it should be treated as a crucial and individual decision based on your specific circumstances and needs. 

In any case, the general rule is to schedule the test when you feel you’ll be freshest and most focused, while also giving yourself at least a few months for review. Some students mistakenly treat the Level 3 as a perfunctory exercise since it’s taken well into residency, but this kind of underestimation is exactly what tricks people into under-preparing as well. 

Preparation for the COMLEX Level 3

Preparation for the Level 3 should ideally begin shortly after beginning the first year of residency, typically about 3 months in. This allows you to totally focus on your program while you get acclimated, while still reserving at least 4-6 months to review, take practice exams, and churn through question blocks.

Like the Level 1 and Level 2-CE exams, the NBOME has created a set of practice exams relevant to the COMLEX Level 3, including the Phase 3 COMSAE exam. Unfortunately, no such Level 3-specific COMAT exam exists per se, but since by this point you’ll have graduated from your COM—who would administer the exam—it’s a moot point. Fortunately, what the NBOME has provided is still quite substantial.

NBOME Tutorials and Practice Exams

The first stop in preparing for your COMLEX Level 3 is to take a diagnostic practice test. Fortunately, the NBOME provides a short 25-question Practice Exam that will acquaint you with the dimensions and domains on the Level 3, and give you a somewhat limited sense of your current baseline. 

Even more helpful for most students will be the CDM-specific materials, both the tutorial and Practice Exam. Both the Level 3 MCQ and CDM practice exams should be taken at the outset and treated as initial diagnostic tools. After this, you can move on to more extensive question bank practice and review, but it’s important to utilize these official resources at the start to provide as clear an understanding of the exam structure and foci as possible.  

COMSAE Phase 3  

The third and final exam in the COMSAE series will be even more helpful than the brief practice exams above, but should still be considered a diagnostic tool—simply a more complete one. The COMSAE Phase 3 covers the same 2 Dimensions as the COMLEX Level 3 and in the same proportions, and is comprised of 300 items, divided into four 50-question sections. As with our advice on the other COMSAE exams (as well as the WelCOM series), we recommend taking the COMSAE Phase 3 in Timed Mode to best simulate the actual testing experience. 

The COMSAE’s major downside, though, is it’s lack of CDM questions, so you’ll still need to find other ways of testing that structure throughout your preparation. Fortunately, as we’ll cover momentarily, there are a number of good resources for CDM cases. 

What to Expect on Exam Day

Exam day for the COMLEX Level 3 will be much the same as it was for the two prior Prometric-based exams, save that you’ll be doing it two days in a row instead of just one.

 You’ll want to arrive at your designated testing center at least 30 minutes ahead of your scheduled testing time. However, if it’s your first time visiting that location—quite likely since you’ll have moved on from your COM to your residency program—we recommend giving yourself a bit more than that, to make sure you’re not rushing to park and navigate a wholly new building. Prometric testing centers are often part of an office suite or park, and so doing some advanced scouting in the days prior to your testing date, to make sure you know the exact location of your testing room ahead of time, will be massively helpful in alleviating stress on test day. 

A 40-minute lunch break is scheduled between the morning and afternoon sessions on each testing day, during which you’ll be able to access your locker to grab any food, drink, or medication you may need. Additionally, there is an optional 10-minute break in the morning between sessions 1 and 2, and between sessions 3 and 4 in the afternoon. Day two provides similar optional 10-minute breaks between sessions 5 and 6, as well as 7 and 8. 

Study Tips

Studying for the COMLEX Level 3, as noted earlier, is sometimes neglected by candidates. This is often due to the busy nature of the first year of residency, but to do well on the exam you absolutely must learn how to study during residency, formulate a comprehensive study plan and stick to it. However, because of the nature of the material being tested, as well as your now extensive experience with COMLEX assessments, this plan can be adjusted to a daily volume a bit more forgiving than what you likely experienced in your Level 1 and 2-CE prep. Additionally, much of your practice throughout Level 3 prep will utilize question banks, possibly more so than during prep for the other two exams, making setting feasible, consistently-achievable daily goals fairly easy.

Question Banks

The big 3 question banks will be of great assistance during your COMLEX Level 3 studying. 

UWorld’s Step 3 bank is a perennial favorite, but for the COMLEX Level 3 it’s not fully sufficient on its own. The lack of Osteopathic Manipulative Medicine (OMM)-specific material, and especially the lack of CDM-structure questions, makes it extremely helpful for most aspects of clinical scenario practice and medical science assessment, but won’t help very much on the section you’re probably fearing the most. UWorld’s CCS block especially can be misleading, as it almost approximates the CDM COMLEX questions, but differs in the answer structure significantly. Still, since you’ll possibly be taking the USMLE Step 3 a short while after taking the COMLEX Level 3, UWorld questions are good to include in your study plan. The subject blocks on Microbiology and Biostats should also be utilized to some extent, as this material is prevalent in every Level COMLEX exam.  

Better for the Level 3’s specific dimensions and questions structures are the TrueLearn and COMQUEST Level 3 banks. Each of these banks features extensive OMM-specific material, and the TrueLearn bank contains quite a few CDM cases formatted specifically to match the COMLEX Level 3. Since the COMLEX Level 3 is a final licensure exam for DOs, studying and working through the OMM-heavy material in TrueLearn and COMQUEST will benefit you far more than it did during the two prior levels of COMLEX exams which are a bit more weighted toward foundational biomedical knowledge and basic clinical science.   

A good study plan would utilize a block of 40 or so UWorld questions each day until you’ve completed the bank, along with similarly-sized blocks of TrueLearn and COMQUEST to better acclimate to the style of the COMLEX exam questions and to cover OMM-specific material. Ideally you want to do about 40-80 questions per day during your heaviest study periods, giving yourself as much time as possible during your study sessions for notes and consult course materials or textbooks for clarification. There will likely be less course material reference involved in studying for the Level 3 but utilizing rotation notes for the CDM material will be especially helpful.


The First Aid series is a staple in COMLEX study, and every candidate should already have a copy of First Aid for the COMLEX from their prior COMLEX exam study periods. This will likely be your go-to reference while working through question banks. This is especially true of UWorld as it doesn’t specifically address OMM material. First Aid for the Step 3 is also helpful for the COMLEX Level 3, and of course is also necessary when you begin studying for the USMLE Step 3.   

Of slightly lesser importance, but still helpful, is The 5-Minute Osteopathic Manipulative Medicine Consult, which can greatly help you refine your navigation of the Dimension 2 and CDM material on the COMLEX Level 3. Lastly, Savarese’s OMT Review is also extremely useful and is loaded with very helpful quick-reference material like charts and mnemonics. OMT Review also comes with access to additional COMLEX-style OMM questions. 

However, none of these books should be treated as primary resources for study. By this point in your development, you should have a firm grasp of most of this foundational information, so don’t worry about dedicating long hours to reading and note-taking for its own sake, but rather use these texts as references for when you get a question wrong, feel fuzzy about a subject or clinical rotation that happened more than a year ago, or just need to verify something you’re unsure of.   

USMLE Step-3 Timing

Timing when you’ll take each of these Level 3 exams will greatly impact your studying, and so it benefits you to have a plan inclusive of both. Of course, many if not most DO graduates do not take the Step-3: if you hoped that choosing osteopathy between DO vs MD programs would save you having to take some of the USMLE exams, you’re finally in luck. If you’ve already been admitted to a residency program, the only licensure exam required for independent osteopathic practice is the COMLEX Level 3. However—and this is a big however—if you plan to apply to a subspecialty fellowship program, you will almost assuredly need the Step-3. If this is your path then you’ll need to make sure you can handle both exams within a few weeks of each other, possibly near the end of your Intern year. 

Because both exams test similar material, and are incredibly grueling experiences, we recommend gearing your studying for the USMLE Step-3 and then spending a week or two reviewing OMM-specific material for the COMLEX Level 3. However, if you’re especially nervous about the CDM material on the COMLEX, or have don’t somewhat poorly on prior COMLEX exams, it could benefit you to arrange more time between. Historically this is not the case—our resident COMLEX expert cautions that big gaps between the two exams at any level usually don’t correlate to improved scores on whichever one you take second. Nonetheless, you can schedule the two however you’d like. We simply recommend taking the Step-3 first if at all possible.  


You’ve done it! The long and bumpy road of COMLEX exams is nearly behind you, and fortunately the Level 3 is indeed more a summation and capstone than a wholly new experience. Nonetheless, one of the major keys to doing well on it is taking it seriously from the outset and not shirking your responsibility to study. With even moderate preparation you can expect to do well on the Level 3, even with its novel CDM section. The hardest challenge will of course be managing your time during your Intern year, but as we’ve shown above your study volume can be adjusted and planned out over a long enough period of time to be quite manageable on both the daily and weekly levels.


1. When should I take the COMLEX Level 3?

Most DOs take the Level 3 sometime before the end of their first year of residency, and we recommend taking it as early in this year as you can to ensure the core clinical and OMM-specific material you’ll have covered in DO school will still be fresh. In general, the further into your Intern year you take the Level 3, the more you’ll have to review and study for it, so taking it early will in most cases be the least demanding option.

2. What is a good score on the COMLEX Level 3?

Although the mean score is 520, any score above a 350 is a Pass, so really anything over 350 is a “good” score. That said, as with most shelf and licensure exams you shouldn’t aim for a specific score but simply do as best you can the first time around, studying intensely in the weeks running up to exam day to maximize your performance. Since you’ll already be admitted to a residency program the numerical score doesn’t matter, but if you start giving yourself unconscious rationales for laziness or poor study planning you can easily end up underestimating the exam and failing.

3. Do DO students take both the COMLEX Level 3 and the USMLE Step-3 exams?

If they’re planning to pursue post-residency subspecialty fellowship training then yes, but for the most part no. Both exams are exhausting and since the Step-3 isn’t totally mandatory for DOs most choose to only take the COMLEX Level 3 and preserve their energy for the residency program.

4. When will my COMLEX Level 3 score be released?

Scores are generally released 8-10 weeks after taking the exam, with some additional delays if you take the exam just before a holiday or break. 

5. Should I take any COMAT exams to prepare for the COMLEX Level 3?

Since COMAT exams are only offered through COMs, you won’t have this option if you’re already in your residency program. However, if you have the opportunity to take the Internal Medicine, OB/GYN, or Osteopathic Principles and Practice COMAT exams sometime during your 4th year of DO school it may benefit you to have another assessment of this material before taking the Level 3, which incorporates a lot of material from these clinical subjects.

6. When should I start studying for the COMLEX Level 3?

Since you’ll want to take it as early into your Intern year as possible, we recommend starting to review and take a diagnostic test before your program starts. That way, you’ll be able to draft a study plan before beginning your program, and have at least that dimension of your life in order while you adjust to residency life. You can always augment or change your study plan as the year progresses, but it’s a lot easier to modify a preexistent plan than it is to create a new one when you’re otherwise busy or feeling overwhelmed.

7. Other than passing the previous COMLEX exams and graduating from my DO program, what do I need to be eligible for the Level 3 exam?

The NBOME also requires an attestation from your residency program director stating that you’re in good academic and professional standing. If you’re one of the rare DO graduates who isn’t pursuing residency, you can petition the NBOME to allow the Dean of your now former COM to issue this attestation.

8. What are Clinical Decision-Making CDM questions?

These questions challenge test-takers with critical or key challenges commonly faced in daily osteopathic practice. They’re structure around a clinical scenario and followed by 2-4 questions. These questions vary from extended multiple choice format—in which one or more answers may be correct—and short answer, in which the test-taker will need to provide a short explanation of data interpretation or suggested treatment. There are 26 such CDM cases on day 2 of the COMLEX Level 3.

To your success,

Your friends at BeMo

BeMo Academic Consulting

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