Authors present the case (from the year 2003) of a 38 years old patient, female with large tumor in the abdominal cavity. Preoperative differential diagnostic examination showed either tumor of pancreas or left liver lobe. The surgery confirmed large tumor body of the pancreas. Histological and immunohistochemical examination determined gastrointestinal stromal tumor (GIST) of the pancreas from autonomous nerves with malignant character. Tumor was radically removed. In the postoperative period regular follow up was done at the department of oncology, abdominal ultrasound every 3 months, CT scan every 6 month. 2.5 years after operation the patient has no problems, CT scan is without signs of recurrent diseases. The analysis of GIST was performed in agreement with contemporary knowledge. According to the references, our case report GIST of pancreas is the first of this kind (till 2003).