From November 1977 through June 1979, 26 of 28 nonuremic patients had forearm arteriovenous fistulas successfully created for dialysis, lymphapheresis or vascular access. To improve patency, aspirin and heparin therapy was begun the night before operation and continued postoperatively in all except one patient. No major change in coagulation parameters resulted from this treatment. Twenty-five radial artery to cephalic vein fistulas were created in 23 patients, brachial artery to basilic vein fistulas in 3 patients, and 8 mm polytetrafluoroethylene brachial artery to basilic vein loop grafts in two patients. Early fistula failures (within 11 days) required thrombectomy once in four patients and twice in another patient. A sixth patient was not given heparin or aspirin and required multiple thrombectomies before the graft was removed because of infection. One other patient refused further surgery after two unsuccessful attempts to create an arteriovenous fistula. In the remaining 26 patients, the fistulas have been successfully maintained, and in 18 patients more than 214 dialysis or lymphapheresis treatments have been performed without problems. The successful establishment of arteriovenous fistulas in nonuremic patients has been achieved by giving aspirin and low dose heparin therapy, which appears to be an integral step in maintaining patency.