After 268 kidney allotransplants, 7 cases of renal artery stenosis were observed. An additional 3 patients were referred to use from another center. The outstanding symptom of all 10 patients was hypertension refractory to medical treatment, beginning not later then 10 months after transplantation. In 9 cases there was a murmur over the transplant. In 6 patients hypertension was accompanied by a deterioration of renal function which was resistant to antirejection therapy. The tentative diagnosis was confirmed by selective renal arteriography of the transplant. Two main types of stenoses could be diagnosed: Segmental stenoses, 0.5-2 cm distal to the anastomosis, which were due to intimal lesions caused during removal of the kidney or by the perfusion canula; and kinking stenoses due to a technically inadequate implantation. Hypertension was controlled in all but 1 patient with reconstruction of the artery. Therefore, hypertension after kidney transplantation refractory to medical treatment should be further investigated with selective renal arteriography of the transplant. Stenoses with clinical symptoms which are confirmed by arteriography should be surgically corrected.