Urokinase, with or without angioplasty, is an alternative to surgical treatment for the treatment of thrombosed polytetrafluoroethylene vascular access grafts. To evaluate the efficacy and outcome of thrombolytic therapy, all available charts of patients with a thrombosed graft treated at the University of California at Los Angeles Medical Center from June 1988 to August 1991 were reviewed. Twenty-three grafts in 21 patients underwent 43 procedures, 17 thrombolytic and 26 surgical, during this period. Four procedures in the thrombolytic group and the surgical group were patent less than 48 hours. Complications occurred in a significantly higher percentage of the thrombolytic group (11 of 17) than the surgical group (two of 26) (p < 0.001). Using life-table analysis, the primary patency was approximately 40 percent at six months and 20 percent at one year in both groups. Urokinase therapy was significantly more expensive than surgical therapy in this study. This increased cost was the result of ten of 17 patients receiving urokinase for more than eight hours. It is concluded that percutaneous delivery of thrombolytic therapy with angioplasty of any documented lesion is as effective as surgical procedure in the treatment of thrombosed hemodialysis access grafts, thrombolytic therapy is associated with a significantly higher complication rate and urokinase treatment that requires more than six to eight hours to lyse the graft thrombus may not be cost-effective.