Primary malignant tumors of the small intestine are uncommon. This infrequency and possible lack of awareness can result in a late diagnosis and a poor survival time. In a period of 34 years, only 55 patients were seen at our cancer institute. The average age of the patients was 56 years, with a male predominance ratio of 2.6:1.0. Twenty-one patients had adenocarcinomas, 19 had sarcomas and 15 had carcinoids. The most common signs and symptoms were abdominal pain and obstruction of the intestine. Preoperative diagnosis was established in 12 of these patients only by roentgenologic barium examination of the small intestine. At the time of diagnosis, 34 of the patients had metastasis to regional lymph nodes or distant organs. The median and five year survival times were one year and 19 per cent, respectively. Patients with carcinoids had better survival rates than those with adenocarcinomas or sarcomas. Palliative resection did not improve survival time. However, if other therapeutic modalities also were used, it might prove beneficial. Patients with palpable abdominal masses or intestinal bleeding, or both, had a worse prognosis than did those presenting with obstruction of the intestine because these are late presenting symptoms. Therefore, recurrent abdominal pain should increase clinical suspicion, and early diagnosis by careful examination of the small intestine with barium contrast material could improve the survival time. Finally, it seemed that these tumors had a high incidence of coexisting malignant conditions, as nine of the patients in our series had a second malignant tumor.