A retrospective review of 547 renal transplants performed over a six-year period revealed allograft renovascular hypertension secondary to RTAS in 39 (7.1%) patients. Percutaneous transluminal angioplasty (PTA) resulted in immediate cure or improvement in 76% of the patients, increasing to 83% in patients with functioning kidneys at a mean follow-up period of 30 months (1-72 months). The renal artery stenosis (RTAS) was equally distributed between living-related and cadaver kidney recipients and did not appear to be more prevalent in end-to-end or end-to-side anastomoses. The blood pressures fell from pre-PTA levels of 167 +/- 22 mmHg systolic to 141 +/- 23.7 post-PTA and 102 +/- 11 mmHg diastolic pre-PTA to 88 +/- 12 mmHg post-PTA (P less than 0.01). Of 25 cured or improved patients, 24 are on significantly less hypertensive medication. Two patients died of causes unrelated to the PTA and only one patient lost a kidney because of the procedure. Compared with operation, PTA is a safer and more effective procedure for the initial treatment of RTAS.