Early onset colorectal cancer (EOCRC) refers to colorectal cancer (CRC) in individuals under age 50. Although the incidence and mortality due to later onset CRC (≥50 years) has been declining over several decades, both are increasing in those under 50. EOCRC is more likely to occur in the distal colon and rectum. There are some unique pathologic and genetic features to these tumors; they are not usually associated with a germline mutation in a gene that predisposes to cancer, and at least some may have a distinct pathogenesis. Initiating CRC screening at an earlier age (40–45 years of age) would presumably detect more early stage and asymptomatic EOCRCs, but this would imply a major additional health care burden. The understanding of EOCRC and the optimal management approach to this problem are unsolved problems.