In an autopsy study of 940 elderly cancer patients, 1,030 cancers were identified. The prevalence rate for overall cancer declined after age 85 in men and after age 75 in women. The chief sites of major cancers were the stomach, lung, esophagus, liver, and pancreas, in that order. Incidental cancers (chiefly of the prostate, thyroid, and colon) were found more often in patients over 80 years old. For multiple primary cancers, the prevalence rate was relatively constant until the age of 70, when it rose to a peak in the 80--84 age group before declining to the original level.