Medical slang is analyzed in the developmental perspective of the physician's career. More than 300 terms gathered by ethnographic methods are classified by social categories: (1) the setting--various types of hospitals and facilities, (2) the players--care-givers and care-receivers, (3) the social processes--patient admission, diagnosis, treatment and discharge, and (4) death and dying. Slang usage generally begins during the third year of medical school when students rotate among clinical services and peaks during the internship year. Male and female clinicians are similar in slang usage. Five psychosocial functions of medical slang are discussed.