Background: Colorectal carcinoma is a disease of older people, with around 90% of patients being over 55 years old, and it is relatively uncommon in patients younger than 40 years, if we exclude populations with hereditary syndrome. Objective: To present our current knowledge of colorectal carcinomas in patients under 40 years of age. Methods: The most relevant papers about colorectal carcinoma in young patients published and indexed on PubMed in the last 20 years were reviewed. Articles were chosen to include those studies that examined patients under 40 years old. Conclusions: Colorectal cancer in young people appears to be a distinct disease, characterized by biological aggressiveness, with unique features such as localization, adverse histologic factors, not associated with prior or concomitant adenomas, advanced stage at diagnosis, and generally worse prognosis.