Gastrointestinal stromal sarcomas, formerly categorized as leiomyosarcomas of gastrointestinal origin, have a common pattern of intraperitoneal dissemination. Despite surgical resection with or without adjuvant systemic chemotherapy the vast majority of these patients succumb to intraperitoneal sarcomatosis and/or hepatic metastases. In an attempt to improve upon the morbidity and mortality associated with this disease we and several other centers have begun treating these patients with intraperitoneal chemotherapy. We have found that aggressive surgical resection with postoperative intraperitoneal chemotherapy has significantly lowered the peritoneal recurrence rate in patients with recurrent gastrointestinal stromal sarcomas as compared to those who have undergone surgical resection alone. However, this treatment approach has proven to be ineffective in preventing hepatic metastases, and thus has had little effect upon overall survival. With the treatment of primary rather than recurrent disease we hope to interrupt the disease process at an earlier stage further decreasing peritoneal recurrences and potentially improving survival.