This study describes the development of benign prostatic hyperplasia among 2,036 volunteers in the Veterans Administration Normative Aging Study, a longitudinal study of human aging situated in Boston. Men were followed from enrollment in the study (between 1961 and 1970) until their last examination prior to May 15, 1982. Two indications of benign prostatic hyperplasia were considered: 1) a clinical diagnosis made at a uniform physical examination, and 2) surgical treatment. Incidence rates for both a clinical diagnosis and surgery for benign prostatic hyperplasia increased through the eighth decade. Life table analysis estimated the lifetime probability of surgical treatment to be 0.29. Known risk factors for cardiovascular disease and diabetes as well as marital and socioeconomic status, religion, cigarette smoking and alcohol and coffee consumption were evaluated as risk factors. Controlling for age in proportional hazards models, statistically significant predictors of surgery were prior clinical diagnosis, lower socioeconomic status, Jewish religion, and not currently smoking cigarettes; whereas only body mass index was a significant predictor of a clinical diagnosis. Although a prior clinical diagnosis was an important predictor of surgery (adjusted odds ratio 3.52, 95% confidence interval = 1.93-6.42), this diagnosis is neither sensitive nor specific in its association with surgery.