A retrospective (1985-2005) multicentric evaluation of the pathological diagnoses of GIST (gastrointestinal stromal tumor) in Hungary was performed. A large cohort of 463 patients with abdominal mesenchymal tumors was reevaluated with the help of immunohistochemistry for CD117, CD34, desmin and S100. Prognostic groups have been established based on international criteria. Two hundred fifty five GISTs have been found in 245 patients during the evaluated period. Beside GIST, 81 leiomyogenic and 25 neurogenic tumors were the primary pathological diagnosis and in 74/255 cases the primary diagnosis was a benign tumor. In our cohort high-risk GIST cases were found to be the predominant. Based on our experience, in case of abdominal tumors of uncertain localization, immunohistochemical markers of CD117, CD34, S100 and desmin provide a proper tool for precise identification of the tumor entity including GIST.