Müllerian duct anomalies are rare in the general population, occurring in less than 3% of women, but much more prevalent in female patients with anorectal malformation, occurring in up to 30% of these patients. Unicornuate uterus with a rudimentary non-communicating horn is a congenital anomaly of Mullerian development which can be seen in isolation or in conjunction with other anomalies, with several case reports described in patients with VACTERL association. These anomalies may be asymptomatic until the patient develops dysmenorrhea or devastating obstetrical complications. We describe the successful surgical management of an obstructive Müllerian anomaly in a post-pubertal female patient with anorectal malformation.