The late manifestations of adult-onset acute bacterial nephritis were studied in 4 patients from 4 mo. to 5.6 yr following initial infection. An unusual combination of generalized (global) wasting of the kidney and focal calyceal clubbing developed within a few weeks of the acute infection. The pattern of calyceal deformity strongly suggests papillary necrosis; it may develop during the acute phase, but go unrecognized during excretory urography at that time because of impaired contrast material excretion. The combination of a small, smooth kidney and papillary necrosis previously has been associated only with the more severe forms of analgesic nephropathy. Observations in these patients indicate that the same urographic findings may also occur as a result of a single earlier episode of acute bacterial infection of the kidney.