IN 1955, a program of functional closure for bladder exstrophy was initiated on the Pediatric Urological Service of Babies Hospital in New York. The experience with functional closure on this Service has now grown to more than 50 cases, and the length of follow-up has exceeded 3 years in enough cases to warrant an interim evaluation of the operative procedure and results. This review is part of a continuing study of functional closure of the exstrophied bladder. Earlier results have been reported previously. Close follow-up has been maintained on these patients in an effort to answer many questions. For example, is functional closure of the exstrophied bladder compatible with preservation of normal renal function and architecture? Is the achievement of urinary continence possible with this operation? Can a satisfactory cosmetic result be expected? The information collected in the quest of the answers to these questions forms the basis for this report. MATERIALS AND METHODS Fifty patients with exstrophy of the bladder treated by functional closure were studied (see Appendix). Thirty-four were males, and 16 were females. All of the cases, with one exception, were patients with complete bladder exstrophy. The one patient with incomplete exstrophy presented with epispadias and exstrophy of the lower portion of the bladder. Forty-two patients were "virgin" cases operated upon by various resident and attending urologists of the Staff. Eight patients were operated upon elsewhere and have been subsequently followed and/or operated upon further at our clinic, or were referred to us for a second attempt at closure.