The registry of digestive tract tumours established for the department of Côte-d'Or was used to study the epidemiologic characteristics of cancer of the small intestine. Over a period of 10 years (1976-1985), 42 new cases were recorded. Age standardized incidence rates, based on world standard population, were 0.7/100,000 for males and 0.4/100,000 for females. As compared with the data from other cancer registries, the risk in Côte-d'Or is in the intermediate range. The mean age was 60.9 years for males and 73.3 years for females (P less than 0.05). Adenocarcinomas represented 40% of the cases, lymphomas 20%, carcinoid tumours 20%, sarcomas 17% and undifferentiated carcinomas 2%. The mean time between symptoms and diagnosis was 4.6 months. Lymph node involvement or metastatic disease were found in 3/4 of the cases at time of diagnosis (31/42). Patients were treated by surgery in 95% of the cases. Curative surgery was used in 23 cases (55%). The post-operative death rate was 13% after curative surgery and 37.5% after palliative surgery. The overall survival rates were 39.9% at 1 year, 19.5% at 3 years and 11.7% at 5 years. Prognosis depended on the stage of diagnosis and the finality of surgical treatment. These results indicate that cancers of the small intestine are rare and difficult to diagnose, explaining the delay in diagnosis and the poor prognosis.