Malignant tumors of the small bowel are unusual and account for only 1% to 5% of all gastrointestinal tract malignancies. Thirteen cases of malignant tumors of the small bowel identified at the VAMC in Puerto Rico from January 1999 to September 2001 and a review of the literature are presented. The mean age of our cases was 67 (range: 45-78). Vague abdominal pain, nausea, vomiting, and melena were the most frequently reported symptoms. The average time from first symptoms to diagnosis was 3.2 months. A positive test for occult blood or hypochromic microcytic anemia was invariably present. Hyperbilirubinemia and increased alkaline phosphatase were warning signs that allowed earlier diagnosis in patients with duodenal tumors. Fifty-four percent of the lesions were detected by endoscopic examination while 46% relied on radiographic studies. Eleven had carcinomas and two malignant gastrointestinal stromal tumors. Neither carcinoids nor lymphomas were identified. Our report of thirteen cases of malignant small bowel tumors is unusual and exhibits differences with the previously reported data. The cases were identified in a limited Hispanic population in a short period of time. Aggressive evaluation and a high suspicion of these malignancies should be entertained whenever subtle symptoms and unexplained gastrointestinal blood loss are assessed.