COMLEX vs. USMLE: Which Exam Should You Prioritize?

For osteopathic (DO) medical students, one of the biggest decisions during preclinical and clinical training is not just what specialty to pursue or where to apply for residency – but now, it is whether to take the USMLE in addition to the COMLEX.

While it was much more common to take both examinations, the merger of the American Osteopathic Association (AOA), the Accreditation Council for Graduate Medical Education (ACGME) and the American Association of Colleges of Osteopathic Medicine (AACOM) in 2020 has shifted the testing landscape as there is now one streamlined accreditation system for graduate medical education (GME).

Both sets of exams are high-stakes, both demand months of preparation, and both can play a decisive role in residency applications. But they are not identical, and the choice to prioritize one or both carries different implications for your career path.

This guide is designed for DO students wrestling with that decision. Here, we will explore the practical differences between COMLEX and USMLE, how program directors view each exam, the pros and cons of taking both, and tutor-informed strategies for making the most of your time and effort.

Understanding the Basics

What is the COMLEX?

 The Comprehensive Osteopathic Medical Licensing Examination (COMLEX-USA) is the licensing exam sequence required for DO students. It is administered by the National Board of Osteopathic Medical Examiners (NBOME) and consists of three levels:

• Level 1: Taken after preclinical years, heavily basic science–focused.
• Level 2-CE: A clinical knowledge exam taken during clinical rotations.
• Level 3: Taken during residency for full licensure.

COMLEX uniquely integrates osteopathic principles and osteopathic manipulative treatment (OMT), which are not covered on the USMLE. It is required for DO licensure in all states.

What is the USMLE?

The United States Medical Licensing Examination (USMLE) is the parallel licensing pathway for MD students, administered by the NBME and FSMB. It also has three steps:

• Step 1: Basic sciences, traditionally the biggest hurdle (now pass/fail).
• Step 2 CK: Clinical knowledge, still scored numerically
• Step 3: Taken in residency.

MD students must take USMLE, but DO students can choose to take it in addition to COMLEX.

Key Similarities and Differences

Although the examinations are similar in nature (i.e. required to obtain a full license), there are some other important differences and similarities between the two examinations:

• Content: Both exams test basic and clinical sciences, but COMLEX uniquely includes OMT while USMLE does not.
• Style: Anecdotally, the USMLE can be a bit more straightforward and clinical vignette–oriented; while COMLEX can possess longer, and sometimes more abstractly worded questions.
• Format: COMLEX Level 1 and Level 2 and USMLE Step 1 and 2 are both one day, while both Level 3 and Step 3 are two day examinations. However, the COMLEX examinations have slightly more questions.
• Resources: Most commercial prep resources (UWorld, Pathoma, First Aid) are geared toward USMLE, though they are also effective for COMLEX. But there are COMLEX specific resources (Truelearn, COMQUEST)
• Scoring:
  • COMLEX Level 1 and USMLE Step 1 are pass fail
  • COMLEX Level 2 and Level 3 and USMLE Step 2 and Step 3 are scored numerically (but all have a minimum passing score)
• Licensure: DOs must take COMLEX to be licensed; USMLE is optional.

Why DO Students Consider Taking the USMLE 

The decision usually hinges on residency applications. Historically, DO students wishing to apply to a program accredited by the ACGME prior to the merger would be required (formally or informally) to report USMLE scores to be competitive with their MD counterparts. Former ACGME accredited program directors were not always familiar with how to equate a COMLEX score to a USMLE score, so DO students were encouraged to take USMLE to make the comparison easier.

However, as we have written before, the merger of the ACGME and AOA in 2020 has made it so that “all residency programs will recognize the COMLEX as comparable to the USMLE, on paper that is. While the American Medical Association recently voted to promote equal acceptance of the COMLEX and USMLE exams by all residency programs, it is unlikely that program directors, who previously only used the USMLE examinations as part of the applicant evaluation process, will immediately adopt this suggestion. It is difficult to directly compare scores from the COMLEX and USMLE, and it is unclear if residency programs will fully adopt the AMA recommendation.”

1. Program Director Familiarity

Program directors at previously ACGME accredited residencies (especially historically allopathic programs) are universally familiar with USMLE scores but may be less comfortable interpreting COMLEX, even though the merger happed a few years ago. While the NRMP data show growing acceptance of COMLEX-only applicants, many PDs still prefer the standardized benchmark of USMLE.

2. Competitive Specialties

If you are eyeing a highly competitive specialty (dermatology, orthopedic surgery, neurosurgery, plastic surgery, interventional radiology), taking the USMLE is often strongly advised. Many applicants in these fields submit both exams, and a solid USMLE Step 2 CK score can help you stand out across both MD and DO students.

3. Geographic Considerations

Some regions, particularly on the coasts and at large academic centers, still remain more USMLE-centric. If you’re targeting residencies in these locations, the USMLE is an advantage. Again, this may change with time as more former ACGME accredited programs fully and truthfully adopt the COMLEX.

4. Fellowship Aspirations

While fellowships generally look at residency performance rather than licensing exams, some academic subspecialties may favor candidates who’ve demonstrated strong USMLE performance.

Why You Might Skip the USMLE 

However, there are also many valid reasons for focusing solely on COMLEX, and COMLEX alone:

1. Time and Stress

Preparing for both exams is a massive time commitment. While the exams overlap significantly, and so will your studying, each examination has some unique components that the other does not possess. Balancing prep for both can add unnecessary stress.

2. Financial Cost

The USMLE registration fees add up (each Step costs around $700–$1,000, not including travel if needed). Combined with COMLEX fees, you’re looking at thousands of dollars. While in the grand scheme of medical school loans this may be an insignificant amount of money, the value you get in taking the USMLE exams may be minimal depending on your particular situation.

3. Specialty Choice

If you’re aiming for primary care (family medicine, internal medicine, pediatrics, psychiatry) or osteopathic-friendly specialties and AOA programs only, many programs openly state that USMLE is not required (and please believe them!). Some even emphasize their commitment to COMLEX-only evaluation.

4. Changing Attitudes

Residency programs have become more accepting of COMLEX scores in recent years, especially since the ACGME and AOA merger. DO students are matching in large numbers without USMLE.

Match Implications: What the Data Show

The NRMP’s annual Program Director Survey is the best window into how exams are weighed.

• Program director key considerations for interviewing included USMLE Step 1, MSPE/Dean’s Letter, and specialty-specific letters of recommendation.
• Among programs who interview U.S. DO applicants, 64% of programs required a pass on Level 1 and Step 1, 24% only required Level 1, 9% only required Step 1, and 4% did not consider either.
• Similarly, 20% of programs who interview U.S. DO applicants prefer a score for Step 2 and Level 2, 17% require a pass for both, and 14% require a target score for both.
• Specialty Differences:
  • Competitive fields (Orthopedics, Dermatology, Neurosurgery): Most programs require either both USMLE and COMLEX scores or USMLE only. Not having them could be a disadvantage and completely eliminate you as a potential candidate
  • Primary care and less competitive specialties: A larger proportion of programs accept COMLEX-only candidates without issue; however, the majority of programs still report requiring both.

Thus, according to NRMP 2024 data, the majority of programs still prefer BOTH COMLEX and USMLE scores; however, this data can is influenced by reporter bias. It is important to consider the individual preferences of the programs YOU are interested in when deciding if you want to take both sets of examinations.

Practical Pros and Cons

Taking Both Exams

Pros:

• Universal comparability with MD peers
• Stronger position in competitive specialties
• More options geographically and across program types

Cons:

• Extra cost and stress
• Double scheduling logistics and studying
• Risk of underperforming on one exam, which could raise questions about the discrepancy

Taking Only COMLEX

Pros:

• Required for licensure anyway
• More time and focus for one set of exams
• Less financial burden

Cons:

• Many programs may screen you out
• Harder to compare directly with MD peers
• Limits access to certain competitive specialties and geographic locations

Tutor Advice: How to Decide

As tutors who frequently work with DO students, here’s the distilled wisdom:

Be Honest About Your Specialty Interest, Geographic Location, and Fellowship Aspirations

 

If you are remotely considering a competitive specialty, strongly consider taking the USMLE – simply to keep this door open. Better to have it and not need it than to need it and not have it!

2. Do not Spread Yourself Too Thin

If you are struggling academically, your best bet may be to focus on one exam – usually COMLEX – rather than risk failing USMLE. A fail is far more damaging than not having a score at all. And, you can still match at MANY programs with COMLEX scores alone.

3. Use Overlapping Resources

Most commonly used preparation materials are geared toward USMLE but these also cover 90–95% of COMLEX content. You can prepare primarily with UWorld and First Aid, then add COMLEX-specific practice (COMBANK, COMQUEST) to get used to the question style and OMT emphasis.

4. Consider the Step 1 Pass/Fail Landscape

With Step 1 now pass/fail, Step 2 CK and Level 2 CE carry more weight. If you are unsure about taking USMLE Step 1, you hypothetically could skip it and instead take only Step 2 CK + COMLEX Level 2. Many DO students have found success with this approach; however, as mentioned before, MANY programs require or request a passing score on both LEVEL 1 and Step 1.

5. Talk to Mentors and Residents

Your school’s match data are a goldmine. Look at where DO graduates matched in your desired specialty, and whether they took USMLE. Talking to residents who have recently gone through the process is invaluable.

A Step-by-Step Framework for Making the Decision

1. Define your career goals. Are you leaning toward primary care or a competitive specialty?
2. Research your specialty. Use NRMP data and talk to advisors about whether USMLE is expected, recommended, or required.
3. Assess your academic standing. If you are comfortably scoring high on practice questions, you are in a good place to tackle the USMLE too. If not, focusing on COMLEX might be smarter and a more judicious use of your time.
4. Plan your timeline. Taking both exams requires careful scheduling and planning.
5. Make a financial plan. Factor in registration, resources, and potential travel.
6. Commit. Once you decide, do not second-guess. A confident, focused study plan beats scattered prep every time.

Special Considerations

Taking USMLE Step 1 but Skipping Step 2 CK

This is generally not advisable. With Step 1 pass/fail, Step 2 CK is the main differentiator. If you go down the USMLE route, Step 2 CK is the score programs will scrutinize while Step 1 is simply a “box to check”.

Taking Only Step 2 CK

This is increasingly common among DOs. Since Step 1 is pass/fail, some students take only COMLEX Level 1 (for licensure) and then add Step 2 CK to pair with Level 2 CE. This strategy minimizes redundancy while maximizing residency competitiveness. Again, be wary of many programs which do request both Step 1 and Step 2 CK.

Failing One Exam

This is a challenging scenario. A failure on either COMLEX or USMLE is far more damaging than not having taken it. If you are unsure, err on the side of caution and focus on one.

Common Myths and Misconceptions

• “You must take USMLE to match at all.” False. Thousands of DOs match every year without USMLE.
• “Programs won’t even look at COMLEX.” Outdated. Many PDs now have policies to evaluate COMLEX equally, and we anticipate the number of programs accepting COMLEX scores to grow each year.
• “If you don’t take both, you’re at a huge disadvantage.” Not universally true. It depends heavily on specialty and region.
• “You can convert COMLEX to USMLE directly.” Only approximate concordance tables exist. They’re not perfect, and many PDs know that and do not know how to reliably interpret these conversions.

Final Thoughts

For DO students, the COMLEX is non-negotiable – it’s your licensing exam. The USMLE, however, is optional. Whether you should take it depends on your career aspirations, residency specialty competitiveness, and comfort with high-stakes testing.

If you are aiming for a competitive specialty, want to maximize your options geographically, or simply prefer having your scores compared directly with MD peers, the USMLE is worth the extra time and effort. If you are confident in your path toward primary care or a less competitive specialty, or if you prefer more DO friendly programs, you may safely focus on COMLEX alone.

What matters most is not the letters in the exam title but how you perform. A strong score on either exam, paired with solid clinical evaluations, research, and a compelling application, will carry you far.