OBJECTIVE The aim of this study was to assess prognosis and treatment of colorectal cancer in young adults. METHODS In a retrospective review of 1,917 patients with colorectal cancer, 80 patients were under the age of 40 years (4.2%). RESULTS The mean follow-up was 5.2 years (range: 0-16 years). There was a family history of colorectal cancer in 20% of the patients, either familial adenomatous polyposis (FAP) or hereditary nonpolyposis colorectal cancer (HNPCC syndrome). Five prognostic factors for the 10 year survival rate were found: stage of tumor in the Astler-Coller classification (A, B1-2, C1-2 and D, 100, 75, 38 and 11% respectively), tumor vascular invasion (16%), poorly differentiated tumors (30%), emergency surgery (21%) and non curative resections (5%). The colon recurrence rate at 8 years was 14% in the case of HNPCC syndrome. The recurrence rate for patients with neither FAP nor HNPCC syndrome was 11.5% at 8 years and for patients alive at 1 year was 16.5%. CONCLUSIONS In patients under the age of 40 years, a subtotal colectomy, even as a second operation should be considered, if the prognostic factors are favorable. A genetic analysis seems to be essential in the management of these patients.