The purpose of this case-control study was to evaluate potential risk factors for prostatic hypertrophy. The cases were 910 residents of Rhode Island who had a partial or total prostatectomy that was not related to cancer in the years 1985-1987. The controls were 2,003 members of the source population who were selected from a list of holders of Rhode Island driver's licenses or a roster of older Americans compiled by the Health Care Financing Administration. Cases and controls were interviewed by telephone. The risk of prostatic hypertrophy was elevated in Jewish men compared with Protestants and Catholics and in blacks compared with whites. Risk was reduced in ever-married compared with never-married men, in men who had left school at age 16 years or more compared with those who had left earlier, and in relatively tall or relatively heavy men. Coffee drinking and cigarette smoking were inversely but only weakly related to prostatic hypertrophy. There was a relatively strong, although irregular, inverse relation of beer drinking to prostatic hypertrophy. The associations of spirits and wine consumption with prostatic hypertrophy were weak.