Data from the population-based cancer registry for Los Angeles County, an area with high risk of AIDS, were used to evaluate secular trends of Kaposi's sarcoma (KS), non-Hodgkin's lymphoma, and other possibly AIDS-related cancers in men aged 18 to 54. Marital status was used as a surrogate for homosexual behavior to compare the proportional incidence rates for the pre-AIDS era, 1972 to 1979, to those for 1980 to 1982 and 1983 to 1985. Both absolute incidence and proportional incidence of KS continue to increase sharply, although in absolute numbers, KS is making a smaller contribution to the total number of AIDS cases as the Los Angeles County epidemic progresses. For never-married men the proportional incidence rate of KS in 1983 to 1985 was nearly 100-fold greater than that of 1972 to 1979 and 7-fold greater than that of 1980 to 1982. High-grade lymphomas show statistically significant secular increases in both never-married and ever-married men, but only the rates of Burkitt's lymphomas have increased to a greater extent in never-married men. A small but significant increase of central nervous system lymphomas is seen in both marital status groups. There is no evidence of any AIDS-related increases in Hodgkin's disease, leukemia, testicular cancer, anal cancer, liver cancer, oral cancer, multiple myeloma, or malignant melanoma. As of 1985, cancer, as a manifestation of AIDS, is still apparently limited to KS and high-grade lymphomas (particularly Burkitt's) in Los Angeles County.