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The Comprehensive Osteopathic Medical Licensing Examination of the United States (COMLEX-USA) is a licensing exam required for students in osteopathic medical schools.
The three-part computer-based examination evaluates your understanding of medical concepts and how well you can apply that knowledge to clinical practice. You must pass all three levels to earn full licensure as an osteopathic physician in the U.S.
Residency program directors also use COMLEX scores when selecting applicants for residency programs. Strong performance can significantly enhance your residency application and signal your readiness for advanced clinical training.
In this guide, we explain what each COMLEX level covers, how scoring works, how the exams compare with the USMLE, and how to prepare effectively as a DO student.
COMLEX-USA Exam Series
There are three levels in the COMLEX-USA series of DO board exams:
- Level 1 focuses on foundational biomedical sciences and osteopathic principles.
- Level 2-CE is a Cognitive Evaluation (CE) that measures your ability to apply clinical knowledge and make safe, evidence-based decisions in patient care scenarios.
- Level 3 assesses the advanced clinical competencies required for unsupervised osteopathic medical practice.
The table below offers a full breakdown of content areas, COMLEX length, and testing format.
| COMLEX-USA Level 1 | COMLEX-USA Level 2-CE | COMLEX-USA Level 3 | |
|---|---|---|---|
| What is tested? | Application of osteopathic medical knowledge, patient care, osteopathic principles and practice, communication skills, professionalism, and ethics | Assesses osteopathic medical knowledge concepts as they relate to clinical sciences and patient care | Assesses patient presentations, seven defined competency domains, and the ability to independently practice as an osteopathic generalist physician |
| When to take it | Near the end of your second year of medical school (M2) | During your third or fourth year of medical school (M4) | During residency |
| Exam length | Eight hours (two computer-based sessions, four hours each) | Eight hours (two computer-based sessions, four hours each) | 14 hours (four computer-based sessions, 3.5 hours each) |
| Number of questions | 352 multiple-choice questions | 352 multiple-choice questions (some involving audio-visual components) | 420 multiple-choice questions, 26 Clinical Decision-Making cases with two to four questions each |
| Score reporting | Pass/Fail | Scaled score | Scaled score |
To take your first of the three COMLEX exams, you must have completed one year of study at an accredited college of osteopathic medicine and be in good academic and professional standing. Osteopathic medical students must pass each level before taking the next exam.Â
The National Board of Osteopathic Medical Examiners (NBOME) recently announced changes to the format of the exam. The number of questions on COMLEX Level 1 and Level 2-CE exams will be reduced to 320, and the two-day Level 3 will be modified to a one-day format. Changes will be phased in starting May/June 2026 for Levels 1 and 2-CE, and January 2027 for Level 3.
Scoring
Each level of COMLEX is scored by converting your raw score, or the number of questions you answer correctly, into a three-digit scaled score. This scaled score accounts for small differences in difficulty across test forms and gives programs a consistent way to compare results.Â
Level 1 reports only a Pass or Fail designation, while Levels 2-CE and 3 include both your scaled score and your pass status.
Passing scores vary by level. Level 2-CE currently requires a scaled score of 400 or higher. Level 3 requires a scaled score of 350 or higher. Although Level 1 is now Pass or Fail, the standard-setting process determines the level of performance needed to earn a passing result.
For all levels, the NBOME ensures that the scoring process is fair and reflects a candidate’s ability to practice osteopathic medicine. The NBOME establishes the passing standard for each level through a rigorous process that involves panels of practicing osteopathic physicians.
Residency program directors rely on COMLEX results to assess an applicant’s academic strengths and clinical readiness. For most specialties, a solid pass meets the requirement for licensure, but competitive programs may expect scores well above the minimum threshold.Â
For example, among matched U.S. DO seniors across specialties, the mean COMLEX Level 2-CE score has been reported to be around the mid‑500s. Scores are still considered within the context of your application.Â
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Pass Rates
Recent data from the NBOME website shows that pass rates for the COMLEX-USA examination remain high across all levels. For the 2024-2025 cycle, first-time pass rates were as follows:
- Level 1: 90.3%
- Level 2-CE: 91.3%
- Level 3: 96.8%
Compared to earlier cycles, the Level 1 exam’s pass rate has remained relatively stable. For Level 2-CE, the pass rate has seen a slight downward drift over recent years but has stayed above 90%. Level 3 continues to show the strongest performance, consistently above 94%, over the last decade.
Although COMLEX pass rates remain strong, the exam is still demanding, with a difficulty level similar to the USMLE. The main difference lies in question style. COMLEX includes osteopathic principles and broader clinical reasoning; the USMLE focuses on basic science integration.
USMLE vs. COMLEX
Both the United States Medical Licensing Examination (USMLE) and COMLEX-USA are licensing exams for medical students, but they cater to different medical programs. USMLE is taken by allopathic (MD) students for NBME accreditation. COMLEX is required for osteopathic (DO) students and overseen by the NBOME.Â
Structurally, both exam series test medical knowledge, clinical reasoning, and decision-making skills, but they differ in emphasis. COMLEX includes osteopathic content at every level; USMLE focuses on biomedical and clinical science without osteopathic principles.Â
DO students are not required to take the USMLE, but some choose to take both to improve residency competitiveness. Taking the USMLE in addition to the COMLEX may be particularly helpful for highly competitive specialties or programs more familiar with USMLE scores.Â
Preparing for both exams requires significant additional time and effort. For many students, excelling on the COMLEX alone is enough for medical licensure and a successful match, especially for training programs that are accustomed to evaluating DO applicants.Â
Ultimately, the decision to take should be based on specialty goals, program expectations, and your personal readiness.
Read Next: MD vs. DO: What’s The Difference + How To Choose
Expert Study TipsÂ
Effective COMLEX test prep starts with planning and a structured approach. Here are a few strategies to maximize your study efforts while maintaining balance:
- Create a realistic study schedule. Map out your study timeline well before each exam to help you cover each subject, track your progress, and avoid last-minute cramming. Many students find that a minimum of three months of dedicated study for each level is ideal.
- Stay engaged during coursework. Put extra effort into your courses to learn and understand the material and avoid cramming later. Take detailed notes, focus on understanding core concepts, and identify weaker areas early.
- Use high-yield question banks. Practice questions are one of the most effective ways to reinforce content and develop test-taking skills. Aim to complete at least 3,000-5,000 practice questions per level across your months of preparation.
- Leverage flashcards and spaced repetition. Flashcards help reinforce high-yield facts. Digital tools like Quizlet allow for spaced repetition, which improves retention over time. Focus on integrating flashcards into daily short study sessions over infrequent reviews.
- Take COMSAEs and practice exams. NBOME practice exams (COMSAEs) help you get a baseline of your knowledge the first time you take them, so you know where to focus your study efforts. Schedule another closer to test day to simulate exam conditions and timing.Â
- Target weak areas early. Continuously track your performance on practice questions and exams. Refine your exam strategy by focusing additional review on subjects or systems where you consistently struggle.
- Prioritize wellness and prevent burnout. Regular sleep, exercise, and breaks are important for effective learning. Incorporate activities that reduce stress, like mindfulness, hobbies, or social time. Avoid overloading study days.
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FAQs
The ideal study duration for DO licensure examinations depends on your familiarity with the material, exam level, and schedule. Most students follow a structured plan combining ongoing review during coursework with a dedicated study period.
For Level 1, many DO students spend three to six months of focused review after preclinical courses. For Level 2‑CE, two to four months of study during or immediately after clinical rotations is common. Level 3 usually requires one to three months, as it builds on prior clinical experience.
Early and consistent review, combined with question bank practice, flashcards, and practice exams, is more effective than cramming. Planning your study schedule around your strengths, weaknesses, and available time is the best way to achieve a passing or competitive score.
From 2004-2020, COMLEX Level 2 was divided into two parts: Cognitive Evaluation and Performance Evaluation (PE). COMLEX-USA Level 2-PE was suspended in 2021 and officially discontinued in June 2022.Â
In response to the discontinuation of Level 2‑PE, NBOME developed a new assessment program, the Core Competency Capstone for DOs (C3DO). This national standardized clinical‑skills assessment is currently being piloted at several colleges of osteopathic medicine.
For now, each student’s COM dean must attest to their specific clinical skills previously tested on Level 2 PE before the student may sit the Level 3 exam. Starting with the class of 2029 and beyond, candidates will need to complete either the C3DO or a similar competency verification to become eligible for the COMLEX‑USA Level 3 exam.
International medical graduates (IMGs) cannot sit for the COMLEX exams. To take the COMLEX-USA exams, a student must attend an accredited college of osteopathic medicine. While there are international osteopathic schools, the Doctor of Osteopathic Medicine degree is only offered by about 40 medical schools in the U.S.Â
You have to take the exams in order. Only after passing Level 1 can you sit for Level 2‑CE, which evaluates clinical knowledge and decision-making. Passing both is required to progress to Level 3 and eventual licensure.Â
The vast majority of residency programs in the U.S. accept COMLEX scores for DO applicants, but highly competitive specialties may prefer USMLE scores. Because of this variability, most advisors recommend that medical students check each program’s current requirements directly.Â
Ace the COMLEX and Get a Guaranteed Score Increase
Passing the COMLEX exams is a huge milestone in the practice of osteopathic medicine. A proper study schedule will take you far in helping you earn your best score.Â
Maximize your performance with expert guidance. Our experienced tutors specialize in COMLEX preparation and help students improve their scores by 105-220 points on average. Â
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Joel Ramirez MD
Dr. Ramirez is an integrated vascular surgery resident at UCSF who is passionate about teaching and tutoring for several board exams. He has served on the University of California, San Francisco School of Medicine admissions committee and is committed to being a leader in medical education.
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