Down's syndrome is the most frequent chromosomal anomaly in humans and sometimes is associated with anorectal anomalies. The anorectal malformations include many varieties of anatomical anomalies, which are often difficult to evaluate. The Authors believe preoperative CT or MRI of the pelvis, together with other clinical and radiological examination to be a valid mean in the preoperative prognostic evaluation. In this study they analysed the association of anorectal malformations and Down's syndrome and the absence of a genito-urinary or perineal fistula.