Alagille syndrome (AS) is characterized by the association of at least three of the following five abnormalities: chronic cholestasis, peripheral pulmonary artery stenosis, vertebral arch defects, embryotoxon, and typical facies. In addition to urological abnormalities, tubulointerstitial nephritis, renal tubular acidosis, and mesangiolipidosis have been noted in AS. The usual manifestations of such renal pathologies rarely include hypertension. We report five patients with at least four of the five major features of AS who developed secondary hypertension of renovascular origin 3.5-28 years after the initial diagnosis of AS. Angiography demonstrated uni- or bilateral renal artery stenosis and various other abnormalities of the main arteries in all five patients: aorta (3 cases), celiac artery (4 cases), superior mesenteric artery (1 case), subclavian artery (1 case). Our findings underscore the value of arterial blood pressure monitoring in patients with AS. If hypertension occurs, a renovascular origin should be sought. The diffuse vascular abnormalities which appeared to be a feature of AS in these patients should prompt larger studies of vascular abnormalities in AS.