If you’re a medical student, you know the big exams are coming. Whether you’re in an osteopathic (DO) or allopathic (MD) program, you’ll need to take a licensing exam, COMLEX Level 1 for DO students, USMLE Step 1 for MD students. But what’s the difference? And should DO students take both?
These exams are more alike than different, but the details matter. Here, Dr. Francis Ihejirika, MD, founder and director of the PASS Program, breaks it down so you know exactly what to expect and how to prepare.
Exam Structure & Format
Both exams are computer-based, multiple-choice tests designed to assess your foundational medical knowledge.
- USMLE Step 1: Focuses on the basic sciences with a clinical application. It’s a mix of straightforward and complex, multi-step questions.
- COMLEX Level 1: Covers the same medical sciences but adds Osteopathic Manipulative Medicine (OMM) concepts.
A key difference? COMLEX has longer*, sometimes vaguer questions, making it harder to quickly find the key info. USMLE questions are more structured and often require multi-step reasoning.
*Total number of questions for COMLEX Level 1&2 will decrease from 352 to 320 in May-June of 2026.
Content Differences: What Each Exam Emphasizes
At their core, both exams test the same fundamental medical knowledge: anatomy, physiology, pathology, pharmacology, and microbiology.
- USMLE Step 1: Heavy emphasis on pathology and pharmacology, with questions designed to apply basic science concepts to clinical scenarios.
- COMLEX Level 1: Tests the same medical knowledge but integrates osteopathic principles, including OMM (15% of questions), patient-centered care, and holistic treatment approaches.
For students taking both exams, make sure you understand OMM concepts for COMLEX while focusing on clinical reasoning for USMLE.
Question Style & Difficulty
This is where students get tripped up.
- USMLE questions: Clear and structured. You’ll be given a patient case, and the answer choices will follow a logical path.
- COMLEX questions: Often longer and more abstract. The test presents extra information, requiring you to filter out what actually matters.
Tip: If you’re used to USMLE-style questions, practice picking out key details quickly for COMLEX.
How Medical Schools & Residency Programs View Each Exam
For DO students, the question of whether to take the USMLE alongside COMLEX depends on residency goals.
- MD students take USMLE only—it’s required.
- DO students must take COMLEX but may also choose to take USMLE for competitiveness in some residency programs.
- IMGs must take the USMLE for ECFMG certification. COMLEX is not available for most international graduates.
In the past, USMLE was more widely accepted, but now many residency programs view COMLEX scores just as seriously. If you’re applying for a competitive specialty or certain MD-focused programs, taking USMLE Step 1 may still be helpful.
Residency Application Impact
The Current Landscape:
- All programs are ACGME residencies and can accept both MD and DO graduates (unified since 2020)
- Program directors are increasingly familiar with COMLEX, but USMLE is still more universally understood
- Competitive specialties may still favor applicants with USMLE scores
For DO Students:
- Research target programs to see if they require/prefer the USMLE
- Many primary care and community programs fully accept COMLEX
- Consider taking Step 2 CK even if skipping Step 1 for numeric differentiation
Scoring: The Big Change
Both USMLE Step 1 and COMLEX Level 1 changed to Pass/Fail in 2022:
- No numeric scores reported
- Includes performance profile for personal use, shifts focus to Step 2 CK for differentiation
Impact: With both primary exams now pass/fail, USMLE Step 2 CK and COMLEX Level 2 scores have become crucial for residency competitiveness.
Common Challenges Students Face
No matter which exam you’re taking, some challenges are universal:
- Time Management – Students often underestimate how much time they need to prepare.
- Question Style Adjustment – Switching between USMLE and COMLEX formats can be tough.
- Over-Reliance on Memorization – Both exams require problem-solving, not just memorizing facts.
To overcome these challenges, practice with question banks that match the exam format and make sure you’re not just memorizing, but truly understanding the material.
Need guidance on test-taking strategies? Subscribe to PASS Programs Online Morning Questions for daily practice and expert insights.
Effective Prep Strategies for Both Exams
So, what’s the best way to prepare?
📌 Pick One Main Resource – Jumping between books leads to confusion. Stick with one structured study guide.
📌 Practice, Practice, Practice – Doing daily practice questions is more effective than passively reading notes.
📌 Know the Exam Style – For COMLEX, practice pulling out key info quickly. For USMLE, work on clinical reasoning skills.
📌 Use a Study Plan – Don’t cram! Start at least 3-4 months in advance and balance review with practice questions.
The PASS Program provides structured study plans that help students master both exams with focused strategies that build confidence and performance.
Common Myths & Misconceptions
Let’s clear up some common myths:
- “COMLEX doesn’t test biochemistry.” – Wrong! Basic sciences like biochemistry are still tested, just in a different format.
- “If I memorize First Aid, I’ll pass.” – Nope! First Aid is great, but both exams require application, not just memorization.
- “You must take USMLE to match into residency.” – Not necessarily! Many DO-friendly programs now fully accept COMLEX scores alone.
Bottom line? Know your target programs and focus on mastering the material, not just memorizing facts.
Conclusion
Both COMLEX Level 1 and USMLE Step 1 are essential exams, and while they have similarities, their differences matter when it comes to study strategies and residency applications.
For DO students, the biggest question is whether to take both exams. If you’re unsure, look at the specific residency programs you’re interested in and decide based on what will give you the best chance.
At the PASS Program, we help students go beyond memorization. Our approach focuses on mastery and test-taking strategy, so you walk into the exam feeling confident.
Want to improve your score? Join the PASS Program today and get expert guidance to help you succeed.
Dr. Francis Ihejirika, MD
Dr. Francis Ihejirika, founder of the PASS Program, emigrated from Nigeria as part of the first refugee family admitted to the U.S. in 1969, later earning his medical degree from the University of Illinois, completing a dual residency in Internal Medicine and Pediatrics, and dedicating his career to helping students succeed on high-stakes exams like the USMLE and COMLEX.
