Colorectal cancer is rare in patients under 40 years of age. We reviewed all colorectal cancer patients treated at the First Department of Surgery of the University of Rome, to determine the true incidence of large bowel cancer in young patients. During the period 1978-1984 a total of 571 patients were indexed. Out of these 44 were 39 years of age or less. A group of 527 patients 40 years of age or over served as a control. Neoplasms were localized in the right colon in 19 cases and in the left colon in 25 patients, in the young group. In the control group 178 patients presented neoplasms localized in the right colon, while 349 presented tumors localized in the left colon. According to tumor advancement in the young group tumor classification from A stage tumor through D stage was: 4, 6, 14, 5, 9, 6. In the control group 22 patients presented A stage tumors, 106 B1, 139 B2, 50 C1, 118 C2, 92 D tumors. The operability rate was 93.2% in the young group, and 92% in the old one. The operative mortality rate was 0% in the young group, and 2.5% in the old one. Four complications occurred in the young patients, and 57 in the old patients. The five years survival rate was 56.7% and 52.1% in young and old patients respectively. The results of our study indicate that there are no significant differences in prognosis and five years survival in young patients with colorectal cancer.