We reviewed clinical records of 34 cases of primary tumors in the small intestine from 1986 to 1990. In total 34 cases, 26 cases were male and 8 cases were female. The mean age was 50.9 year. Benign tumors were 6 and malignant tumors were 28. The most common symptom of benign tumors was abdominl pain (83%) followed by anemia (50%) and intussusception (33%). The most common symptom of the malignant tumors was also abdominal pain (86%) followed by weight loss (50%), anemia (43%), constipation (43%), and palpable mass (39%). Leiomyoma was the most common benign tumor and adenocarcinoma was the most common malignant tumor. Adenocarcinomas occured predominatly in the duodenum and malignant lymphomas occured prednminantly in the ileum. In the duodenal tumors, the detectabilities of endoscopy and upper GI series were 79% and 77%, respectively. In the jejunal and the ileal tumors, the detectabilities of small bowel series were 50% and 71%, respectively and those of abdominal computed tomogram were 30% and 33%, respectively. The accuracy of preoperative diagnosis in pathology was 32% and only 65%. of patients could be diagnosed to have small intestinal tumors before surgery.