The value of pulsed Doppler velocimetry (PDV) to detect renal graft artery stenosis was evaluated in a prospective study of 42 kidney-transplanted adult patients. The results of PDV were compared with those of arteriography which is regarded as a reference examination. With PDV the diagnostic sensitivity was 85 percent and specificity was 82 percent. The low cost and good sensitivity (provided the interpretation problems are known) of this harmless examination make it a good instrument to detect renal graft artery stenosis. In order to obtain an early diagnosis, 148 kidney-transplanted patients were systematically examined by PDV 1, 3, 6 and 12 months after transplantation. The incidence of renal graft artery stenosis was evaluated at 6.8 percent.