The prevalence of adenomas at autopsy is compared with the incidence of colorectal carcinomas within a defined population in northern Norway. The study shows that females are more inclined to develop adenomas than males at ages up to 55 years, which corresponds with the higher cancer incidence in younger females than males before the age of 65 years. At older ages males have both a higher prevalence of adenomas and a higher incidence of carcinomas than females. When the data are analysed in accordance with anatomical segment and age, a change in predilection site of adenomas from the distal part of the large intestine at younger ages to the proximal part at older ages was found in both sexes. A similar relative change in the subsite distribution was also found for carcinomas, but only in males, and about 10 years later.