Background: Herlyn-Werner-Wunderlich (HWW) syndrome is an uncommon variant of Mullerian duct anomalies, consisting of uterine didelphys, obstructed hemivagina, and ipsilateral renal agenesis. It usually presents in a post-pubertal adolescent or adult woman in whom hematometrocolpos produces a pronounced mass effect and pain on the side of the obstructed hemivagina. Case Report: We report the case of a 13-year-old girl who presented to the emergency radiology department with sudden onset of severe pain at the right lower quadrant of the abdomen; imaging confirmed the diagnosis of HWW syndrome. Why should an emergency physician be aware of this?: When unilateral renal agenesis and uterus didelphys coexist, the first thing that the physician should remember is to confirm or refute the presence of a blind vagina for diagnosis of HWW syndrome. (C) 2015 Elsevier Inc.