Because doubts remain about the safety and efficacy of renal transplantation for patients with primary urological abnormalities, we have studied the outcome of transplantation in a large group of such patients. Between 1977 and 1989, 69 renal transplants were completed in 62 patients with abnormal lower urinary tracts (29 primary vesicoureteric reflux, 13 posterior urethral valves or bladder outflow obstruction, 6 vesicoureteric tuberculosis, 5 neuropathic bladders, and 9 miscellaneous causes). Graft survival in this urological group was similar to that in 150 allograft recipients (157 grafts) with end-stage renal failure of a non-urological cause. No aetiological subgroup had poorer graft survival than the others, although patients with recurrent urinary-tract infections and a history of outflow obstruction tended to have worse graft function. 9 patients (10 transplants) had renal transplantation into a urinary diversion (8 ileal conduits, 1 rectal bladder). These patients had graft survival and renal function comparable with those of the whole urological group. We found no effect of immunosuppressive treatment (cyclosporin or azathioprine), type of kidney donor (living or cadaveric), or donor or recipient age on graft survival time or renal function. Thus, renal transplantation in patients with abnormal lower urinary tracts is safe and effective; patients with ileal conduits do well and have few substantial difficulties. Preoperative assessment of bladder emptying and urodynamics are important in these patients.