Transplant renal artery stenosis (TRAS) is a common complication after transplantation and an important cause of graft dysfunction. Many factors have been implicated as possible causes of TRAS, such as damage from trauma and atherosclerosis. We reviewed all 286 patients transplanted in our unit from January 1990 to July 1997 to study the prevalence, clinical features, and diagnostic and therapeutic approach. Thirteen patients with TRAS were identified, and their mean age was 40 +/- 15 years. The detected incidence was 4.5%. They were treated with triple therapy (prednisone, azathioprine and cyclosporine A). The mean age of the donors was 28 +/- 27 years. TRAS was diagnosed within nine months after transplant. All patients were studied with Doppler ultrasound, renography with captopril and angiography. The preferred initial therapy was percutaneous transluminal balloon renal angioplasty. Angioplasty was performed in four patients with good results. Two patients underwent surgery because angioplasty was not possible. Blood pressure control could be achieved with less antihypertensive medication after angioplasty. Transplantectomy was performed in one patient because of surgical complications. In conclusion, most patients with TRAS can be treated successfully with percutaneous transluminal angioplasty as the initial interventional treatment of choice for high-grade renal artery stenosis, and surgical revascularization is indicated when percutaneous transluminal angioplasty cannot be done or is unsuccessful.