Eight children with thrombo-embolic disease in the course of nephrotic syndrome were treated at II Clinic of Children's Diseases (Institute of Pediatrics, Poznań) between 1991 and 1993. The diagnosis was established on the basis of clinical examination and noninvasive imaging techniques. Two patients had an atypical localisation of the thrombus in the left ventricle and right atrium. In laboratory tests of the coagulation system, all of the children had decreased levels of antithrombin III (AT III). All children were treated with heparin and 4 with fibrinolytic agents. AT III concentrate was administered to 3 children. Total resolution of thrombo-embolic disease was obtained in 5 patients, 3 died during treatment. Thrombo-embolic disease should be taken into account in the differential diagnosis of complications of nephrotic syndrome.