Congenital disorders of development are more common than previously reported and the correct diagnosis is frequently missed leading to suboptimal treatment. Eight cases of uterus didelphys with obstructed hemivagina referred to the Gynecology service at Baylor College of Medicine over a 2-year period were reviewed. Initial presenting symptoms and signs were followed by an incorrect diagnosis by the referring physician 100% of the time. MRI, the most sensitive imaging modality for congenital anomalies (Kublik, RA: Female pelvis. Eur Radiol 1999; 9:1715), was utilized in only 50% of the cases. In this group of patients, hematocolpos and pyocolpos were discovered in equal numbers upon exploration. Ipsilateral renal anomalies were present 100% of the time, while coexisting contralateral anomalies were present 50% of the time. Resection of the vaginal septum was required for abatement of symptoms in all cases presented here. Laparoscopy provided additional information beyond radiologic tests regarding pelvic and urological anatomy. In two cases, resection of the ipsilateral uterine horn was required. These cases demonstrate the difficulty in diagnosis, heterogeneity in presentation, and need for expertise not only in this rare congenital anomaly but also all the other disorders of development of the female genital tract.