Gastrointestinal stromal tumors (GIST) are the example of very rare sarcoma of alimentary tract. In the presented material, 5 cases of GIST were diagnosed and treated in our Department. One tumor was localized in stomach, two in rectum and one in jejunum. Primal localization of the last tumor was not discovered. It was visualized between rectum and bladder, covered by the omentum. In each case confirmation of the diagnosis was done on the basis of the immunohistochemical staining--CD117(+). In four cases surgery was the primary treatment. Only in one case radical resection was performed. In other three cases radical resection was not possible due to the presence of liver metastases (in two cases) and the size of the tumor (20 x 10 cm). One patient was disqualified from the surgical treatment. Four patients were qualified for the chemotherapy with imatinib. In one case, patient did not undergo the treatment. In the group treated with imatinib the early reply was satisfactory. On the ground of our material we conclude that patients usually begin the treatment in the advanced stage of the disease. When the GIST diagnosis is probable, one has to broaden the histopathological examination with immunohistochemical staining for CD117 antigen. Making the right diagnosis is crucial for patients, since imatinib is effective even in the advanced stages of the disease. Nevertheless radical surgical treatment is still the primary choice for the patients with GIST.