Intraperitoneal (IP) urokinase is a fibrinolytic agent that has been used in the adjunctive treatment of continuous ambulatory peritoneal dialysis (CAPD) and resistant and relapsing peritonitis. However, its efficacy and role in treating resistant CAPD bacterial peritonitis remain unclear and results from previous prospective studies have been conflicting. We prospectively randomized 88 CAPD patients with bacterial peritonitis resistant to initial empirical IP antibiotics into two groups: IP urokinase 60,000 IU and a placebo group. Patients were treated concomitantly with susceptible antibiotics according to culture results. Peritoneal dialysate grew pseudomonas aeruginosa in 13 patients (14.8%), non-pseudomonas bacteria in 63 patients (71.6%) and negative cultures in 12 patients (13.6%). For the clinical outcomes, there were no significant differences in the primary response rates (61.4 vs. 50%), relapse rates (9.1 vs. 13.6%), Tenckhoff catheter removal rates (22.7 vs. 29.5%) and mortality rates (6.8 and 6.8%) between the urokinase group and the controls (p=ns). Subgroup analysis of culture negative patients (n=12) also demonstrated no sgnificant benefit for urokinase treatment. No significant adverse effects were encountered with the IP urokinase instillation. Total median peritonitis-related length of hospitalization for the urokinase group and controls were 7 and 11 days, respectively (p=0.32). We concluded that IP urokinse plays no significant role as an adjuvant therapy in the treatment of bacterial CAPD peritonitis resistant to initial IP antibiotic therapy.