A 27 year old woman presented for investigation of primary infertility. She was found to have complete longitudinal vaginal septum and cervical duplication with two endometrial cavities. Laparoscopy demonstrated a normal uterine contour. Saline infusion sonohysterography and diagnostic hysteroscopy revealed two completely separate uterine cavities, each communicating with its own cervix. This case sets sight on the contribution to the incidence of this inimitable mullerian anomaly, one that is inconsistent with our current understanding of Mullerian development. An alternative embryological mechanism is reviewed to account for this and other anomalies which do not fit into existing classification systems.