INTRODUCTION: Gastrointestinal stromal tumours (GIST) are mesenchymal tumours of the digestive tract originated in the interstitial cells of Cajal. They express the tyrosine kinase c-kit (CD117) activity receptor. Mutations in this receptor cause neoplastic development. Curative treatment continues to be radical resection of the tumour and is resistant to commonly employed chemotherapy regimens. Imatinib mesilate is a drug that inhibits c-kit activity expressed by GIST and its activity in these tumours has been demonstrated. MATERIAL AND METHODS: Retrospective study of all cases of leiomyoma, leiomyosarcoma, schwannoma, and stromal or mesenchymal tumors from 1989 to July 2004. C-kit and CD34 proteins were detected at immunohistochemical study in addition to the usual markers for mesenchymal tumours. RESULTS: 49 GISTs were diagnosed, 26 males and 23 females (mean age 64.1). Symptoms were digestive tract bleeding (n = 13), abdominal pain (n = 13), intestinal occlusion (n = 4) and others. The lesion was located in small bowel (n = 22), stomach (n = 19), rectum (n = 3), peritoneum (n = 2), esophagus (n = 1), omentum (n = 1), and retroperitoneum (n = 1). Forty-three of the 49 patients underwent surgery; radical resection was performed in 37 (75.5%) and palliative surgery in the other six (16.2%). Two of the patients that did not undergo surgery received chemotherapy. At the time of study, 28 (57.14%) patients remained alive, 23 (46.9%) of whom were disease- free and five (10.2%) were not. Nineteen (38.7%) patients died. CONCLUSIONS: The results of our series are similar to the others published. Before the year 2001, surgery was the only successful option for the GIST. Surgical resection continues being the best treatment to definitively cure this disease. Imatinib is used to treat not only resectable tumours, but even to allow the possibility to make a subsequent rescue surgery. On the other hand, Imatinib is used in the treatment of the metastatic disease.