Gut stromal tumors (GST) are a group of intramural intestinal tumors formerly known as leiomyoma and leiomyosarcoma. To improve the understanding of GST behavior, we posed the following questions: What are the clinical sequelae? Do size and symptoms correlate? What are the indications for excision? A retrospective analysis (1988 to 1996) of the clinical course for GST patients was completed including long-term follow-up. We found 39 patients with GST during the last 8 years. Their average age was 65 years and 59% were male. Tumors were found in the small bowel or stomach in 95% of cases. All patients were treated by surgical excision. Histologic grading yielded a benign diagnosis in 77%. Tumors were found incidentally at laparotomy in 41% and had an average size of 1.5 cm. In contrast, 59% of GST patients were symptomatic and the average size was 6 cm. In these 23 symptomatic patients, gastrointestinal bleeding occurred in 70%, of which acute hemorrhage was seen in 69-82% of them required transfusion and half required emergent operation. Additional findings in the symptomatic group included abdominal pain (57%), bowel obstruction (30%), and perforation (9%). An average long-term follow-up of 2.5 years was obtained in all patients (n = 34, 5 had died of other causes). Local recurrence was seen in 2 patients, metastatic disease in 2 other patients, and 30 (88%) were disease free. No patient with a GST discovered incidentally has had it recur. Gut stromal tumors are uncommon yet cause significant patient morbidity. Small GST (<2 cm) were asymptomatic but larger GST were usually symptomatic. Most GST behaved in a benign fashion after local resection. Due to the frequency of serious complications in symptomatic patients, complete excision is recommended for GST, even if incidentally discovered.