The incidences of the cancer of the oesophagus, stomach, small intestines, colon, and rectum for the years 1971--1977 in the regional district of North Baden, Federal Republic of Germany are presented and their relation to environmental factors are discussed briefly. The age specific incidence as well as the age standardized incidence and the sex ratios show remarkable differences due to the specific tumor localizations. The colon cancer incidence in the female population increases steeply during the period considered. The risk of developing rectal cancer also increases. The results of the pathoanatomic registry are well comparable with the data from clinical registries.