Cancers of the digestive organs and peritoneum constituted 28% of all cancers in Denmark in 1943-87. The lack of a common trend in incidence rates for the different tumour types indicates different aetiologies. Survival is worst for cancer of the oesophagus and improves gradually for cancer of the stomach, cancer of the small intestine and colorectal cancers. Survival from these tumours differ little between the sexes, but females have a slightly more favourable prognosis, which is most pronounced for sites with the best survival. The changes in survival over the study period, 1943-87, show virtually no change in the prognosis for oesophageal cancer, very slight, if any, improvement in that for stomach cancer, a detectable improvement in survival from cancer of the small intestine and substantial improvements in survival from colorectal cancer. Survival rates after colorectal cancer appear to be lower in Denmark than those seen in the USA. This finding may be due to the exclusion of certain precancerous lesions from the Danish material, which is not possible in US studies. Cancers of the liver, gallbladder and pancreas all carry extremely high mortality rates, with five-year survival rates below 5%, and one-year survival rates below 5% for cancers of the liver and pancreas.