Two cases of primary adenocarcinoma of the colon are presented. Patient C.P. had a highly undifferentiated, signet ring type of adenocarcinoma and survived only 3 months. Patient P.G. had a well-differentiated adenocarcinoma with early, adequate resection of the lesion and has survived 8 years with no evidence of recurrence. The literature on carcinoma of the colon in children under 17 years of age is reviewed. There are twice as many boys with this disease as girls. Abdominal pain, vomiting, constipation, weight loss, blood in the stool, abdominal distension, and anorexia were common symptoms. The most common physical findings were the presence of an abdominal mass, abdominal distension and tenderness, anemia, and dehydration. These signs and symptoms are similar to those seen in adults with this disease. Approximately 50% of these children had a highly invasive, signet ring type of adenocarcinoma on microscopic examination. This type of carcinoma is rare in adults. Those patients with a signet ring type of adenocarcinoma have a very poor prognosis. However, the remaining 50% had well-dif-ferentiated adenocarcinoma where early diagnosis and adequate surgical resection could reduce the mortality.