The age-specific cumulative prevalence of clinically diagnosed prostatism among 1,057 generally healthy men followed for up to 30 years in the Baltimore Longitudinal Study of Aging was compared with the age-specific autopsy prevalence of pathologically defined benign prostatic hyperplasia (BPH) from a published compilation of five independent autopsy studies involving 1,075 prostates. Clinical prevalences based on medical histories and digital rectal examinations showed excellent agreement with autopsy prevalences at all ages. Despite the well-known lack of correspondence between prostatism and objective urologic evidence of BPH in individual patients, these results suggest that the proportion of the male population with clinically recognizable prostatism by a given age is about the same as the proportion with pathological evidence of BPH.