Congenital abnormalities of the genitourinary tract often coexist, and cryptorchidism is common in patients who have had imperforate anus. Twenty men who had pull-through procedures for imperforate anus in infancy have been evaluated for infertility. Seven had coexisting renal abnormalities, 4 had had recurrent epididymitis, 3 had had bilateral orchidopexies (at age 7 to 12), 2 had spina bifida, and 1 had a pituitary adenoma. Seven had no ejaculate (aspermia), 11 were azoospermic, 1 was severely oligozoospermic, and 1 had a normal sperm concentration in a small volume of ejaculate. Both vasa were blocked in 5 men, and this appeared to be a result of the original operative procedure. One vas was blocked in another 7 patients who had abnormalities on the contralateral side; three had epididymal blocks after epididymitis, and four had congenital malformations associated with an absent or ectopic kidney. After reconstruction (4), insertion of sperm reservoirs (4), microscopic epididymal sperm aspiration (2), or artificial insemination (1), sperm were retrieved from 9 men (ejaculated by 4) 2 pregnancies occurred. Male infertility after treatment of imperforate anus in infancy can be related to a wide variety of cause, some of which are amenable to treatment.