Records of 72 consecutive patients with caliceal diverticula, representing an incidence of 4.5 per 1,000 excretory urograms, were studied. Of these 72 patients, 39 per cent had a history of recurrent infections and an equal number had stone-containing diverticula. However, only 17 per cent had roentgenographic evidence of pyelonephritis. Similarity of incidence in children and adults, as well as a paucity of renal infection and scarring, supports an embryologic etiology. In our experience the need for surgical intervention is much less than is suggested in the literature.