Background/Aims: The aim of the study was to present, on the base of own experience, clinical importance of arterio-venous fistulae involving the vascular system of the abdomen. Methodology: Clinical material consists of 18 patients in whom abnormal arterio-venous leakage in the abdomen Was disclosed by means of imaging diagnostic techniques and Doppler sonographic hemodynamic investigations. Three groups of patients were determined: 1. Patients in whom arterio-venous fistula was a primary cause of portal hypertension (N=6), 2. Patients in whom the presence of arterio-venous fistulae aggravated portal hypertension due to other pathology (N=7). 3. Patients in whom the arterio-venous fistulae did not directly affect portal flow (N=6). As each case presented a different clinical problem, the therapeutic approach had to be individualized. In 12 patients perarterial embolization was performed, 13 patients were operated on, one,patient was listed for liver transplantation. Results: Perarterial embolization was fully effective only in 4 cases. In the remaining 8 cases its effect was transient, but in 4 cases of liver tumors it allowed us to proceed with chemoembolization and the others were subsequently treated surgically. In 12 surgically treated patients the operation proved to be curative. In 1 case of multiple arterio-venous fistulae related to diffuse angiomatosis, surgical procedure was unfeasible. One patient, awaiting liver transplantation, died of liver failure. Conclusions: 1. Arterio-venous fistulae (of various etiology) are rarely found in the abdominal cavity, but their presence means usually serious. consequences depending on their morphology and localization. 2. Arterio-venous fistulae involving the portal system may result in severe portal hypertension. 3. Individually chosen method of treatment, aimed at the occlusion of arterio-venous fistula often proves to be curative. 4. Overlooking or ignoring the presence of intraabdominal arterio-venous fistulae leads to unsuccessful, if not harmful treatment.