669 patients who received a renal transplant from January 1988 to December 1993 at a single institution were evaluated for urologic complications. Urologic complications were assessed and categorized by organ involvement: kidney, ureter, bladder, lymphatic, calculus and complicated urinary tract infection. Complications were also classified as "early" if they occurred within 14 d after transplant and those diagnosed after this period were called "late." The management of all complications is presented. There were a total of 98 urologic complications identified in 669 patients, of which 51 were complicated urinary tract infections. The other 47 complications were divided among renal (8), ureteral (19), bladder (3), lymphatic (10) and calculi (7). Preventive measures, such as technical management of ureteral reimplantation, periodic renal scan or ultrasound examinations, and long-term urinary antibiotic prophylaxis could further reduce the incidence of urologic complications. The result should be further improvement in transplant patient and graft survival.