Background: Colorectal adenocarcinoma rarely occurred in adolescent.Clinical feature and prognosis of this population are not clear until now.In addition, DNA mismatch repair (MMR) status may relate to the early disease occurrence.The present study aimed to perform a retrospective analysis of adolescent patients with colorectal cancer, including clinicopathological characteristics and prognosis.Methods: The medical records of 11,503 patients diagnosed as colorectal cancer in Cancer Hospital, Chinese Academy of Medical Sciences from January 1999 to December 2009 were retrospectively reviewed.Finally, 19 patients who were between 10 and 20 years old were selected as the study group.We summarized the clinicopathological characteristics, analyzed the association with prognosis and assessed the expression of MMR protein by immunohistochemical method.Results: The most common primary site was the right colon in 7 patients.Ten patients had Stage Ⅲ colorectal cancer, 5 patients had Stage Ⅳ disease.Signet ring cell carcinoma was the most fiequent pathological type (7/19).Deficient MMR was identified in 2 patients.The 5-year survival rate and median survival time were 23.2％ and 26 months.Distant metastasis was identified as an independent prognostic factor (P =0.02).Conclusions: Colorectal cancer in Chinese adolescents was very rare.The chinese adolecents with colorectal cancer were frequently diagnosed in the right colon, as Stage Ⅲ/Ⅳ disease with signet ring cell carcinoma.The prognosis was relatively poor.