Experience with the diagnostic evaluation and operative management of 38 hypertensive patients having bilateral renal revascularization is presented. Twenty-four patients had atherosclerotic occlusions and 14 had fibromuscular dysplasia. Renal vein renin assays (RVRA) and/or split renal function studies (SRFS) were performed in 37 of the 38 patients before operation. Although RVRA was negative in 29 percent and SRFS negative in 31 percent, 24 of 26 patients (92 percent) having both tests done had at least one positive study. Twenty-one patients had simultaneous bilateral repairs and 12 had staged bilateral reconstructions. The incidence of technical failures in these two groups was 21 and 9 percent, respectively. Excluding three uncorrected technical failures and two patients with recurrent branch renal artery lesions, 90 percent of patients with atherosclerosis and all patients with fibromuscular dysplasia had a favorable blood pressure response to operation. This study supports the use of both RVRA and SRFS in the diagnostic evaluation of hypertensive patients with renal artery stenosis. If these functional tests lateralize to one side, repair of that side only is recommended. If the functional studies do not lateralize, operation is suggested only when hypertension is severe and is not controlled readily with medications. In this circumstance reconstruction of the side that appears to be diseased most severely is recommended. Contralateral repair is undertaken only when hypertension persists and when repeat functional studies lateralize to the unoperated side.