USMLE (United States Medical Licensing Examination) is a three-step exam conducted by the National Board of Medical Examiners (NBME) and the Federation of State Medical Boards (FSMB) in the United States. The USMLE exam is required for medical graduates who wish to practice medicine in the United States.

The three steps of the USMLE exam are:

1. USMLE Step 1: This is the first step of the exam, which tests the candidate’s knowledge and understanding of basic sciences such as anatomy, biochemistry, physiology, and pharmacology. The Step 1 exam is a computer-based test that consists of 280 multiple-choice questions that must be completed in one day.
2. USMLE Step 2: The Step 2 exam is divided into two parts – Step 2 Clinical Knowledge (CK) and Step 2 Clinical Skills (CS). Step 2 CK tests the candidate’s knowledge and understanding of clinical sciences such as internal medicine, surgery, pediatrics, obstetrics and gynecology, psychiatry, and preventive medicine. Step 2 CS tests the candidate’s clinical skills in patient care and communication. Step 2 CK is a computer-based test, and Step 2 CS is a hands-on exam that tests the candidate’s ability to interact with patients.
3. USMLE Step 3: The Step 3 exam tests the candidate’s knowledge and understanding of patient management and clinical decision-making. The exam is a computer-based test that consists of 318 multiple-choice questions and must be completed in two days.

The USMLE exam is required for medical graduates who wish to obtain a medical license to practice medicine in the United States. The exam is also required for graduates who wish to enroll in a residency program in the United States. The USMLE exam is recognized by medical licensing authorities in the United States and other countries.