200+ Free USMLE Step 1 Practice Questions

Pass your United States Medical Licensing Examination Step 1 exam on the first try — instant access, no signup required.

✓ No registration✓ No credit card✓ No hidden fees✓ Start practicing immediately

93% Pass Rate

200+ Questions

100% Free

Loading practice questions...

Same family resources

Explore More USMLE

Continue into nearby exams from the same family. Each card keeps practice questions, study guides, flashcards, videos, and articles in one place.

USMLE Step 2 CK

Practice Questions260 questions 1 video 1 blog

USMLE Step 3

Practice Questions234 questions 1 video 1 blog

More From This Family

Videos and articles for deeper review.

VideoUSMLE Step 1 Exam Guide 2026: FREE Pass/Fail Plan + May 14 FormatThis exam VideoUSMLE Step 1 Exam Guide 2026: FREE Pass/Fail Plan + May 14 Format VideoUSMLE Step 1 Exam Guide 2026: FREE Pass/Fail Plan + May 14 Format ArticleUSMLE Step 1 Exam Guide 2026: FREE Pass/Fail Plan + May 14 Format42 min read

2026 Statistics

Key Facts: USMLE Step 1 Exam

93%

U.S. MD First-Taker Pass Rate

USMLE 2025

280

Maximum Questions

USMLE Content Outline

Total Testing Time

USMLE

Question Blocks

USMLE

44-52%

Pathology Content

USMLE Content Description

$695

Exam Fee

2026 USMLE Fee Schedule

USMLE Step 1 transitioned to Pass/Fail scoring for exams administered on or after January 26, 2022. The exam has up to 280 multiple-choice items in an 8-hour testing session. Before May 14, 2026, the format is 7 blocks of up to 40 items; on and after May 14, 2026, the format changes to 14 blocks of up to 20 items. The exam emphasizes integrated systems-based thinking and clinical vignettes requiring application of basic science knowledge to patient-care scenarios.

Sample USMLE Step 1 Practice Questions

Try these sample questions to test your USMLE Step 1 exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 200+ question experience with AI tutoring.

1A 45-year-old man presents with fatigue and jaundice. Laboratory studies show elevated unconjugated bilirubin. Which enzyme deficiency is most likely responsible for this presentation?

A.Glucose-6-phosphate dehydrogenase

B.UDP-glucuronosyltransferase

C.Phenylalanine hydroxylase

D.Homogentisic acid oxidase

Explanation: UDP-glucuronosyltransferase is responsible for conjugating bilirubin in the liver. Deficiency (as in Gilbert syndrome or Crigler-Najjar syndrome) results in unconjugated hyperbilirubinemia. G6PD deficiency causes hemolytic anemia with indirect hyperbilirubinemia but is not an enzyme deficiency in the liver conjugation pathway.

2A 2-year-old child presents with developmental delay, intellectual disability, and a musty odor to the urine. Which dietary restriction is essential for this patient?

A.Galactose

B.Phenylalanine

C.Fructose

D.Leucine

Explanation: Phenylketonuria (PKU) is caused by phenylalanine hydroxylase deficiency, leading to accumulation of phenylalanine and its metabolites. The musty odor is from phenylacetic acid. Treatment requires lifelong restriction of phenylalanine intake.

3A researcher is studying a signaling pathway where a ligand binds to a receptor tyrosine kinase, leading to cell proliferation. Which of the following is the most likely downstream signaling molecule in this pathway?

A.cAMP

B.Ras protein

C.IP3

D.Nitric oxide

Explanation: Receptor tyrosine kinases (RTKs) typically signal through the Ras-MAPK pathway for cell proliferation. cAMP is associated with G-protein coupled receptors (Gs), IP3 with Gq-coupled receptors, and nitric oxide with soluble guanylate cyclase signaling.

4A 6-month-old infant presents with fasting hypoglycemia, hepatomegaly, and lactic acidosis. A liver biopsy shows glycogen accumulation. Which enzyme deficiency is most likely?

A.Glucose-6-phosphatase

B.Glycogen phosphorylase

C.Branching enzyme

D.Debranching enzyme

Explanation: Glucose-6-phosphatase deficiency (von Gierke disease or Type I glycogen storage disease) presents with severe fasting hypoglycemia, lactic acidosis, hyperuricemia, and hepatomegaly due to glycogen and fat accumulation in the liver.

5A patient with a history of alcohol abuse presents with neurological symptoms including ophthalmoplegia, ataxia, and confusion. Which vitamin deficiency is most likely responsible?

A.Vitamin B12

B.Thiamine (Vitamin B1)

C.Folate

D.Niacin

Explanation: The triad of ophthalmoplegia (CN III, IV, VI palsies), ataxia, and confusion is classic for Wernicke encephalopathy caused by thiamine deficiency, commonly seen in alcoholics. Untreated, this can progress to Korsakoff psychosis.

6A newborn presents with lethargy, vomiting, and jaundice shortly after introducing breast milk. Laboratory studies show elevated galactose and galactitol in the blood. Which enzyme is deficient?

A.Galactokinase

B.Galactose-1-phosphate uridyltransferase

C.Lactase

D.Aldolase B

Explanation: Classic galactosemia is caused by galactose-1-phosphate uridyltransferase deficiency. Symptoms appear with lactose/galactose ingestion and include vomiting, jaundice, hepatomegaly, cataracts, and intellectual disability if untreated.

7A patient with chronic granulomatous disease develops recurrent infections with catalase-positive organisms. What is the underlying defect in this condition?

A.Defective neutrophil chemotaxis

B.Defective NADPH oxidase complex

C.Defective CD18 integrin

D.Defective myeloperoxidase

Explanation: Chronic granulomatous disease (CGD) is caused by defects in the NADPH oxidase complex, preventing the respiratory burst and superoxide generation needed to kill catalase-positive organisms like Staphylococcus aureus, Burkholderia cepacia, and Aspergillus.

8A cell line is found to have a mutation in the p53 gene. Which cellular process is most likely impaired?

A.DNA repair and cell cycle checkpoint control

B.Protein synthesis initiation

C.Lipid metabolism

D.Glycolysis regulation

Explanation: p53 is the "guardian of the genome" that regulates cell cycle checkpoints (G1/S arrest), DNA repair, and apoptosis in response to DNA damage. Loss of p53 function is the most common genetic alteration in human cancers.

9A patient presents with muscle weakness and myoglobinuria after vigorous exercise. Which metabolic pathway is most likely impaired?

A.Gluconeogenesis

B.Glycogenolysis

C.Fatty acid oxidation

D.Ketogenesis

Explanation: Fatty acid oxidation defects (e.g., carnitine palmitoyltransferase II deficiency) are the most common cause of recurrent rhabdomyolysis and myoglobinuria triggered by prolonged or vigorous exercise, fasting, or illness, because muscle cannot use fatty acids for energy once glycogen is depleted. They also present with non-ketotic hypoglycemia and cardiomyopathy. McArdle disease (glycogenolysis defect) classically causes a 'second wind' phenomenon with early-exercise cramps rather than rhabdomyolysis from sustained exertion.

10Which enzyme catalyzes the rate-limiting step in cholesterol synthesis?

A.HMG-CoA synthase

B.HMG-CoA reductase

C.HMG-CoA lyase

D.Acetyl-CoA carboxylase

Explanation: HMG-CoA reductase catalyzes the conversion of HMG-CoA to mevalonate, the rate-limiting step in cholesterol synthesis. It is the target of statin drugs. HMG-CoA lyase is involved in ketogenesis, and acetyl-CoA carboxylase is the rate-limiting enzyme in fatty acid synthesis.

About the USMLE Step 1 Exam

USMLE Step 1 assesses foundational understanding of health, disease, and therapeutic principles across organ systems. Current official system ranges include Reproductive & Endocrine Systems (12-16%), Respiratory & Renal/Urinary Systems (11-15%), Behavioral Health & Nervous Systems/Special Senses (10-14%), Blood & Lymphoreticular/Immune Systems (9-13%), Multisystem Processes & Disorders (8-12%), Musculoskeletal/Skin/Subcutaneous Tissue (8-12%), Cardiovascular System (7-11%), Gastrointestinal System (6-10%), Social Sciences/Communication (6-9%), Biostatistics/Epidemiology/Population Health (4-6%), and Human Development (1-3%). Discipline coverage is mechanism-heavy, with pathology (45-55%) and physiology (30-40%) carrying the largest ranges.

Questions

280 scored questions

Time Limit

8 hours; 7 x 60-minute blocks before May 14, 2026, changing to 14 x 30-minute blocks on/after May 14, 2026

Passing Score

Pass/Fail (since January 2022)

Exam Fee

$695 (FSMB and NBME)

USMLE Step 1 Exam Content Outline

12-16%

General Principles

Biochemistry, molecular biology, cell biology, genetics, immunology, microbiology - foundational sciences applied clinically

9-13%

Behavioral Health & Nervous System

Psychology, psychiatry, neuroscience, and neurological disorders with emphasis on clinical presentation and mechanism

9-13%

Reproductive & Endocrine

Male and female reproductive systems, pregnancy, endocrine physiology and pathology, hormone regulation

9-13%

Respiratory & Renal

Pulmonary physiology and pathology, acid-base balance, renal function, electrolyte disorders

7-11%

Blood & Lymph

Hematopoiesis, coagulation, anemia, leukemias, lymphomas, immune-mediated blood disorders

6-10%

Multisystem Processes

Shock, sepsis, multisystem organ failure, autoimmune diseases, infectious diseases affecting multiple systems

6-10%

Musculoskeletal & Skin

Bone and joint disorders, connective tissue diseases, dermatology, wound healing, trauma

5-9%

Cardiovascular

Cardiac physiology, electrophysiology, congenital and acquired heart disease, vascular pathology

5-9%

Gastrointestinal

Digestive physiology, liver and pancreatic function, GI pathology, nutrition, metabolic disorders

4-6%

Biostatistics & Epidemiology

Study design, statistical interpretation, public health, screening test characteristics, evidence-based medicine

How to Pass the USMLE Step 1 Exam

What You Need to Know

Passing score: Pass/Fail (since January 2022)
Exam length: 280 questions
Time limit: 8 hours; 7 x 60-minute blocks before May 14, 2026, changing to 14 x 30-minute blocks on/after May 14, 2026
Exam fee: $695

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

USMLE Step 1 Study Tips from Top Performers

1Master pathology mechanisms - understand the 'why' behind disease processes, not just facts

2Practice clinical vignettes extensively - Step 1 emphasizes application of basic science to patient scenarios

3Use spaced repetition for memorization-heavy topics like microbiology, pharmacology, and biochemistry

4Focus on high-yield systems: general principles, cardiovascular, respiratory, renal, and GI

5Review biostatistics thoroughly - these concepts are often under-studied but consistently tested

Frequently Asked Questions

What is the USMLE Step 1 pass rate?

In 2025 USMLE performance data, Step 1 first-taker pass rates were 93% for U.S. MD examinees, 89% for U.S. DO examinees, and 75% for non-U.S./Canadian examinees. Pass/fail scoring began for exams administered on or after January 26, 2022.

How is USMLE Step 1 scored?

Since January 26, 2022, Step 1 outcomes are reported as Pass/Fail only. USMLE notes that the passing standard corresponds to 196 on the prior three-digit scale, but future Step 1 passing-standard reviews will not be reported as three-digit scores.

How many questions are on USMLE Step 1?

Step 1 contains up to 280 multiple-choice items in one 8-hour testing session. Before May 14, 2026, the exam is divided into 7 blocks of up to 40 items; on and after May 14, 2026, it changes to 14 blocks of up to 20 items.

How long should I study for Step 1?

Most students dedicate 4-8 weeks of dedicated study time, with 6-8 hours of focused study daily. Total preparation typically spans 6-12 months of ongoing review during preclinical years plus dedicated study period.

What is the best way to prepare for Step 1?

USMLE states that broad-based learning in the basic sciences is the best preparation, and examinees should use the official content outline, sample test materials, and self-assessment resources. Focus on mechanisms and clinical applications rather than rote memorization.

Can I retake Step 1 if I fail?

Yes, you can retake Step 1 up to 4 times total, with a maximum of 3 attempts within a 12-month period. You must wait 28 days between attempts.