NBOME
COMLEX Level 1
Comprehensive Osteopathic Medical Licensing Examination of the United States, Level 1
The first of three licensure exams every osteopathic (DO) medical student must pass, testing foundational biomedical sciences and osteopathic principles. Pass/fail since 2022 and required to progress toward DO licensure.
What's on the exam
COMLEX-USA Master Blueprint, Level 1 (Dimension 2: Clinical Presentations — NBOME publishes minimum percentages summing to 85%; weightPct scales them to 100)
Community Health and Patient Presentations Related to Wellness
≥12% (minimum)Preventive medicine · Epidemiology and biostatistics · Health promotion · Population health · Medical ethics
Human Development, Reproduction, and Sexuality
≥5% (minimum)Embryology · Reproductive physiology · Pregnancy and fetal development · Genetics and inheritance · Lifespan development
Endocrine System and Metabolism
≥5% (minimum)Hormone signaling · Glucose regulation and diabetes · Thyroid and adrenal disorders · Metabolic pathways · Nutrition and vitamins
Nervous System and Mental Health
≥10% (minimum)Neuroanatomy · Neurophysiology · Neuropharmacology · Behavioral science · Psychiatric pathophysiology
Musculoskeletal System
≥13% (minimum)Anatomy of the spine and extremities · Osteopathic structural diagnosis · OMT principles and techniques · Somatic dysfunction · Rheumatologic pathology
Genitourinary/Renal System and Breasts
≥5% (minimum)Renal physiology · Acid–base balance · Nephron pathology · Genitourinary anatomy · Breast pathology
Gastrointestinal System and Nutritional Health
≥10% (minimum)GI anatomy and histology · Digestive physiology · Hepatobiliary function · GI microbiology · Nutritional deficiencies
Circulatory and Hematologic Systems
≥10% (minimum)Cardiac physiology · Cardiovascular pathology · Hemostasis and coagulation · Hematologic malignancies · Cardiovascular pharmacology
Respiratory System
≥10% (minimum)Pulmonary physiology · Gas exchange and transport · Respiratory pathology · Pulmonary infections · Acid–base compensation
Integumentary System
≥5% (minimum)Skin anatomy and histology · Dermatologic pathology · Skin infections · Immunologic skin disorders · Wound healing
Frequently asked questions
How much does the COMLEX Level 1 cost?
The COMLEX Level 1 costs $745. $745 NBOME examination fee; NBOME states fees are frozen at 2025 levels through the 2027–2028 cycles.
How long is the COMLEX Level 1 and how many questions does it have?
320 items (reduced from 352 beginning with the May 2026 test cycle) — About 8 hours of testing plus breaks (one day).
What do you need to pass the COMLEX Level 1?
Pass/fail against the NBOME standard (numeric scores discontinued in 2022).
Can you retake the COMLEX Level 1?
Retake permitted only after a failing attempt; limited to four total attempts per examination.
What is the best way to study for the COMLEX Level 1?
Start from the official outline and your primary study materials: the exam is weighted by domain (Community Health and Patient Presentations Related to Wellness ≥12% (minimum), Human Development, Reproduction, and Sexuality ≥5% (minimum), Endocrine System and Metabolism ≥5% (minimum), Nervous System and Mental Health ≥10% (minimum), Musculoskeletal System ≥13% (minimum), Genitourinary/Renal System and Breasts ≥5% (minimum), Gastrointestinal System and Nutritional Health ≥10% (minimum), Circulatory and Hematologic Systems ≥10% (minimum), Respiratory System ≥10% (minimum), Integumentary System ≥5% (minimum)). Once you've learned the material, spaced-repetition flashcards organized by those domains are an efficient way to retain it and refresh it before test day.
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