We present our experience with the intracorporeal injection of papaverine and duplex sonography in the assessment of 47 patients with suspected vasculogenic impotence. Sonography and Doppler analysis were performed before and after the papaverine injection. The anatomy of the penis was easily seen. Flow in the deep arteries was obtained in most patients in both the flaccid and erect state. Patients with a good erectile response to papaverine injection had a larger increase in the inner diameter of the deep cavernosal artery than did those with a poor response. However, the percentage change in the diameter did not correlate with the degree of clinical response. Following injection, the systolic peak flow rates and diastolic minimum flow rates were higher in patients with some clinical response but only the increase in diastolic flow rates correlated in a stepwise fashion with the degree of clinical response. This technique provides a method for the objective assessment of response to intracorporeal papaverine injection. Its potential as a diagnostic test will only be determined after normal values are established. At present it appears most useful in patients responding poorly to papaverine injection by indicating the possible area of vascular impairment and the direction for further evaluation.