Step 3

Step 3 or USMLE Step 3

Physician Certification

The USMLE is a three step examination that assesses a physician's ability to apply knowledge, concepts and principles that are important in health and disease, and that constitute the basis of safe and effective patient care. Used by medical licensing authorities in the US for granting initial license to practice medicine.

The third step, typically referred to as Step 3, is the final step for physicians.  All House Officers are required to pass Step 3 before they may begin their third year in any residency program. 

http://www.usmle.org/step-3/