A study of 59,070 cancers newly diagnosed during the years 1978 through 1982 among black and white males and females was conducted to assess variations in age-adjusted incidence rates across four marital categories, single, married, divorced, and widowed. Population data were obtained from the 1980 Census. Distinct patterns of cancer incidence by marital status were observed for black and white males and females. Single black males had the highest age-adjusted incidence rates for all 15 of the 15 sites analyzed among men. Similarly single black females' rates were highest for 14 of the 18 sites analyzed among women. Among white females, age-adjusted incidence rates were highest or second highest in widows for 16 of 18 sites analyzed. The variation in cancer incidence by marital status was not statistically significant for white men. In addition, there is a statistically significant concordance of cancer incidence by marital status across the four race-gender groups for three digestive tract sites. Clues to cancer etiology are suggested by this study, as well as potential directions for preventive health programs.