The treatment of the urogenital sinus with normal rectum still represents a challenge. A perineal approach with or without a skin flap seems to be effective for those patients with a low implantation of the vagina. However, in patients with a high vaginal implantation, this treatment frequently fails to provide a good, functional vagina due to a narrow, strictured vaginal opening. Based on previous experience in the treatment of more than 80 patients with a persistent cloaca, a posterior sagittal transanorectal approach with a protective colostomy was performed in three patients with urogenital sinus and normal rectum. The pelvis was approached through a midsagittal posterior incision; the coccyx was split and the entire anorectal sphincteric mechanism was divided in the midline. The rectum was bivalved in the midline including both posterior and anterior rectal walls. This provided excellent exposure to the urogenital sinus. The vagina was then fully separated from the urogenital sinus (as described in cases of persistent cloacas), and then mobilized and sutured to the perineum. The rectum and sphincteric mechanism were meticulously reconstructed. A midline incision assures the preservation of anorectal innervation, and provides excellent exposure to the pelvis. Anal dilatations are not necessary to maintain a patent and supple anorectal opening because the rectum has two suture lines, one in front of the other. After the colostomy was closed, all patients had appropriate bowel control for their age; two of them are fully continent for urine and the third one still has a suprapubic cystostomy tube waiting for a repair of an additional urethral malformation.