Large increases in prostate carcinoma incidence rates from 1988 to 1992, followed by sharp declines, in several U.S. cancer registries have been attributed to the impact of screening. Trends may vary by age, racial and/or ethnic group, and geography. Trends in prostate carcinoma incidence rates between 1988 and 1994 were examined by age group and race (African American and white), using data from the population-based Connecticut Tumor Registry. Incidence rates for all stages combined rose from 1988 to 1992 and then declined for men age 65-74, 75-84, and 85 + years; however, as of 1994, no decline was evident for those age 45-54 and 55-64 years. Distant stage rates declined after 1991 for men age 65-74 and older, but not for younger age groups (in which increases in rates had occurred for all tumor grades among locoregional stage cancers). Trends in age-standardized rates were similar for African Americans and whites in Connecticut, but larger increases in Utah suggested regional differences in screening rates. Temporal trends in prostate carcinoma incidence in elderly men in Connecticut were consistent with the impact of screening, but the explanation for trends in younger men was less clear, indicating the need for continued monitoring.