COMLEX Exams: What You Need To Know

April 25, 2024
5 min read


Reviewed by:

Akhil Katakam

Third-Year Medical Student, Lewis Katz School of Medicine at Temple University

Reviewed: 4/25/24

If you’re an osteopathic medical student or an aspiring one and want more information on the COMPLEX exams, this guide will tell you everything you need to know!

Whether you’ve just begun applying to osteopathic medical school or have already been accepted into your dream med school, you’ve likely already heard of the COMLEX exams; or will soon. 

These exams are essential parts of your journey to becoming an osteopathic doctor, so it’s important you know exactly what they are and what they test.

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What Are the COMLEX Exams?

The Comprehensive Osteopathic Medical Licensing Examination (COMLEX) is a series of exams osteopathic medical students must complete in order to practice osteopathic medicine. 

These exams are required in order for students to not only receive their Doctor of Osteopathic Medicine (DO) but to be eligible for entry into residency training programs.

How Hard is COMLEX?

The difficulty of the exams really depends on a few factors.

  • What You Know: If you have a strong grasp of the material from your medical school education, some parts of the COMLEX may come easier to you.
  • How You Study: Your study habits and how well you prepare matter. Good study methods and using the right study materials can make the exams seem more manageable.
  • Test-Taking Skills: How you handle the test itself is crucial. This includes managing your time during the exam, understanding what the questions are asking, and using clinical reasoning.
  • Stress and Anxiety: Feeling nervous about the exams can make them seem harder than they are. It's helpful to find ways to manage stress and anxiety, like practicing relaxation techniques.
  • Passing Standards: What's considered a passing score can change from year to year, so it's important to keep up with the current requirements.

In simple terms, how hard the COMLEX feels depends on how well you prepare, your background knowledge, and how you handle the stress of the exams. Preparing effectively and staying calm during the tests can make a big difference. Good luck!

How Long is COMLEX?

The COMLEX-USA Computer-Based Examinations are split into two separate 4-hour sessions. Candidates will be granted a total of 60 minutes of break time, which they can utilize during three scheduled breaks between the two sessions.

How Many COMLEX Exams Are There?

There are a total of four exams students must pass in order to become licensed DOs. Each of these exams tests different competencies and is meant to provide a comprehensive assessment of students’ knowledge, fluency, and clinical skills.

Students must successfully complete these exams in sequence; they must pass the previous exam to be eligible to write the next. 

COMLEX Level 1

This first exam is a one-day computer assessment that is meant to be taken after students have successfully completed their first year at an accredited college of osteopathic medicine. 

COMLEX Level 1 tests on foundational biomedical sciences and clinical problem-solving and health promotion knowledge. It focuses on testing the following osteopathic competencies:

  • Medical knowledge
  • Patient care
  • Principles and practice
  • Communication skills
  • Professionalism
  • Ethics

The exam consists of two four-hour long test sessions and 352 multiple-choice test questions.

COMLEX Level 2: Cognitive Evaluation

The second exam is also a one-day computer exam that is meant to be taken after students have successfully completed their second year of osteopathic medical school.

This exam builds on knowledge tested on the first COMLEX exam but focuses on assessing competencies related to the clinical care of patients and health promotion in supervised clinical settings.

This exam tests on the following clinical science disciplines:

  • Emergency Medicine
  • Family Medicine
  • Internal Medicine
  • Obstetrics/Gynecology
  • Osteopathic Principles and Practice
  • Pediatrics
  • Psychiatry
  • Surgery

Like the first exam, this exam consists of two, four-hour test sessions with 352 multiple choice questions. 

COMLEX Level 2: Performance Evaluation 

The third exam is a one-day on-site examination that is also meant to be taken after students complete their second year of osteopathic medical school. 

This exam is different from the rest because it’s based on patient presentations and assesses students’ interactions with patients.

This exam requires students to interact with 12 standardized patients, spend 14 minutes on each case, and another nine minutes documenting their findings. It tests the following humanistic skills:

  • Physician-patient communication
  • Interpersonal skills
  • Professionalism

It also tests the following biomedical skills:

  • Medical history-taking
  • Physical examination
  • Principles and osteopathic manipulative treatment
  • Documentation 

The third exam is considered to be one of the hardest, and if you’re stressing about completing it, there’s good news! This exam has been postponed until further notice, meaning you might not have to complete it at all!

COMLEX Level 3

The final exam is a two-day computer-based examination that is meant to be taken after students have graduated from their DO program and have earned their degree.

This exam aims to test students’ foundational competency required to deliver safe and effective osteopathic medical care in unsupervised environments as independently practicing osteopathic generalist physicians.

The following clinical disciplines are tested:

  • Emergency Medicine
  • Family Medicine
  • Internal Medicine
  • Obstetrics/Gynecology
  • Osteopathic Principles and Practice
  • Pediatrics
  • Psychiatry
  • Surgery

As of January 2022, this exam will also include questions testing students’ knowledge of COVID-19.

The test consists of four, three, and a half-hour long test sessions taken over two days. There are 420 multiple choice questions and 26 clinical decision-making cases that contain two to four multiple choice or short answer questions each. 

COMLEX Vs. USMLE: What Is the Difference?

As an aspiring doctor, you've probably heard of the USMLE as well. These exams are similar to the COMLEX because they’re also licensing exams. The United States Medical Licensing Examination (USMLE) is a three-step examination for medical licensure typically taken by MD students.

While MD students have to complete these exams to become licensed, DO students do not. These exams are optional for DO students, but are often taken by DO students interested in applying to MD residency programs. 

While the USMLE is usually not required for DO students to apply to MD residencies, having USMLE scores makes it easier for admissions committees to compare DO and MD students


In case you have any remaining questions, here are the answers to frequently asked questions about the exams.

1. Is COMLEX Harder Than USMLE?

There are mixed opinions on which exam is harder. But, in general, the COMLEX is considered slightly harder because it’s longer, usually has an additional exam (it’s postponed indefinitely currently), tests more material, and is less predictable.

2. What Is the Difference Between USMLE and COMLEX?

The USMLE is required for MD students to practice medicine, the COMLEX is required for DO students. 

4. What Does COMLEX Stand For?

It stands for Comprehensive Osteopathic Medical Licensing Examination.

5. Which COMLEX Exam Is the Easiest?

The final COMLEX exam has the highest pass rate. In recent years, 97.1% of test-takers passed on their first try. This is likely because students are familiar with the test format and have already completed their DO, meaning they have a good grasp on osteopathic knowledge and practice. 

6. Which COMLEX Exam Is the Hardest?

The first exam is typically the hardest because it’s new to students and covers a lot of material. The third exam is also considered to be difficult because it’s an in-person exam with patients.

Final Thoughts

While the COMLEX exams are extensive and overwhelming, their completion marks major milestones in your osteopathic journey. Each exam you complete puts you one step closer to achieving your dream of becoming an excellent osteopathic doctor!

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