Incidence was derived from published data from 2 population-based registries-the Philippine Cancer Society-Manila Cancer registry and the Department of Health-Rizal Cancer Registry, which covered 8.5 million residents (1990 census) of a 1,674 square kilometer area that comprises Metro Manila and Rizal province. Thirteen registry clerks actively sought new cancer cases in 96 hospitals and 30 Civil Registry offices. Both registries are members of the International Association of Cancer Registries and receive continuing professional assistance from the International Agency for Research on Cancer (IARC). For the period of 1988-1992 the combined age-standardized incidence rate (ASR) was 17.0, prostate cancer ranked third and comprised 6.1 per cent of all male cancers. Prostate cancer rates were lower than those observed among North American and European populations, but within the Asian region, Philippine rates were higher than most Asian populations. Age-specific rates increased considerably at age-group 66-59 years and continued to increase with increasing age. There were significant differences in rates between cities and municipalities, with the rates in some highly urbanized cities double those seen in urbanizing areas, and triple those seen in rural areas. Rates had increased slightly in the 13-year period between 1980-1992 but total cases had triples. Incidence rates among Filipino migrants to Hawaii, San Francisco and Los Angeles were almost 3 times higher than rates seen in Philippines residents, but were still only half of those seen among the white populations.