Prostate cancer is the second leading cause of cancer death among United States men, with rates among blacks twice those among whites. Over time, mortality has increased among nonwhites but has changed little among whites. Earlier reports have predicted that the rise among nonwhites would diminish because it appeared that those born in the late 1800s were at highest risk. Based on 1950-1989 United States mortality data and populations at risk estimated using census data, we assessed prostate cancer mortality trends over time in white, nonwhite, and black men. From 1950-1954 to 1985-1989, age-adjusted prostate cancer mortality rates increased slightly for whites (9%) but substantially for nonwhites (67%). Among whites, rates increased over time in men over age 80 years but remained constant for younger men. Among nonwhites, rates increased steeply in those above age 74 years and slightly in the age group 65-74 years but declined in those under age 65 years, with the rate of decrease much more rapid in those under 55. The predicted reduction in risk among nonwhite men born since 1900, reported in an earlier study based on the mortality pattern through 1970, has not occurred because rates continued to increase among older nonwhites. In summary, prostate cancer mortality rates are rising among older men and decreasing in nonwhite young men. While improved detection of the cancer may partly account for the trend, analytical studies are needed to investigate the reasons for the increase in prostate cancer mortality in older men, the decrease in nonwhite young men, and the increasing excess risk among blacks.