The purpose of this study was to determine if time trends in cancer incidence among the elderly in Hawaii were similar to the trends observed in the mainland United States and to determine if the trends were comparable among the various ethnic groups living in Hawaii. Average annual incidence rates per 100,000 persons, age 65 or older, were determined by sex and ethnicity for the time periods 1973 to 1977 and 1983 to 1986 through the Hawaii Tumor Registry, a population-based central cancer registry. The incidence of all cancers combined increased 27% among men and 26% among women between the 2 time periods. Similar to the rest of the United States, melanoma and cancers of the brain, lung, colon, breast and prostate have risen substantially among elderly Hawaii residents. Comparisons across ethnic groups revealed that melanoma increased mainly among Caucasians, lung cancer increased primarily among Hawaiians and Caucasians, and colon cancer increased in all ethnic groups.