Urinary retention in male patients after renal transplantation may cause serious complications in terms of graft function and even patient survival. Only few data concerning the management and outcome of these patients are reported in the literature. Therefore, we retrospectively analyzed the outcome of patients who underwent transurethral incision of the prostate immediately after renal transplantation. Between 1990 and 1993, we performed 259 renal transplantations and 15 patients had symptoms of urinary retention postoperatively. These patients underwent a midline transurethral incision of the prostate from the bladder neck to the verumontanum. Median peak flow preoperatively was 7 ml. per second (range 0 to 11.4) and median residual urine volume was 100 ml. (range 30 to 500). Median prostate volume was 28 ml. (range 12 to 45). After transurethral incision of the prostate a significant improvement (p < 0.001) in peak flow rates (19.6 ml. per second, range 8 to 49) as well as a significant decrease in residual urine volumes (40 ml., range 20 to 80) could be achieved. After a median followup of 19 months the effect was still present.