Adenocarcinoma of the colon is an unusual disease in patients under 30 years of age, and generally presents as advanced disease because of a lack of awareness of its occurrence, especially in the pediatric age group. The authors report on 2 cases of colon cancer in children less than 17 years old, whose initial presentations were abdominal pain of unclear etiology and non-specific abdominal complaints. No other abnormal laboratory results were found except that 1 patient had anemia. Barium studies revealed the typical colon lesions in both patients, and colonoscopic pathologic examination disclosed mucinous adenocarcinoma. The first patient was rather unusual in that 2 separate tumors were found simultaneously in the large intestine. The therapeutic approach included surgery and adjuvant chemotherapy, but both patients ultimately died due to poor response and early recurrence. Survival obviously depends on the extent of the disease at diagnosis; the earlier the diagnosis is, the better the prognosis will be. Clinical characteristics, diagnosis, and treatment of colon cancer in pediatric patients are discussed.