An enhanced frequency and morbidity of urinary tract infections (UTI) have been observed in association with alcoholism and liver disease. The causes of these phenomena may relate, in part, to the defects in humoral and cellular immune mechanisms that occur in alcoholism. Urinary catheterization is the most common cause of UTI in hospitalized alcoholics. The severity of the sequelae of UTI in alcoholism is demonstrated by the unusually frequent occurrence of renal papillary necrosis (RPN) in conjunction with pyelonephritis in these patients. Indeed, in over 90% of the reported cases of RPN occurring with alcoholism or liver disease, pyelonephritis has been a contributing factor. The proclivity to medullary ischemia and RPN in this patient group may be, at least in part, a result of interstitial renal edema secondary both to infection and the effect of ethanol per se and to renal arterial vasoconstriction that occurs in cirrhosis. The frequency with which death due to sepsis or renal failure occurs in association with UTI in alcoholics obliges the physician to exercise caution in the prevention and treatment of UTI in these patients.