To review the experience of the Milan University First Department of Obstetrics and Gynecology in patients with double, didelphic, or bicornuate uterus, blind hemivagina, and ipsilateral renal agenesis, and to consider the frequently unsatisfactory surgical approach. Thirty-six women with double, didelphic, or bicornuate uterus, blind hemivagina, and ipsilateral renal agenesis were identified from clinical records for the period 1962 to 1992. We evaluated demographic data, disease, symptoms, correctness of therapeutic approach, and definitive treatment. Seventeen patients previously had undergone incomplete surgery in other hospitals and 19 were treated by us for the first time. Total hysterectomy was performed on two of the 36 women and hemihysterectomy and hemicolpectomy were performed on four. In the other 30, the vaginal septum was excised and marsupialization was done. The pregnancy rate in the 15 women wanting children was 87% and the live birth rate was 77%. Serial biopsy specimens were obtained from the lateral fornix after the excision of the septum in 13 of the 30 non-hysterectomized patients over 1–9 years and revealed progressively more extensive areas of squamous metaplasia of mullerian epithelium. In some isolated cases, papillary hyperplasia, mild dysplasia, and vaginal adenosis were found. At the end of follow-up, 16 patients still did not want children. Follow-up was possible in 34 cases. Early accurate diagnosis after menarche followed by excision and marsupialization of the blind hemivagina offers complete relief of symptoms and preserves reproductive potential. Partial morphologic changes are evident but metabolic modifications comparable to those of the adjacent normal vagina have not yet been documented.