Uterine didelphys with obstructed hemivagina and ipsilateral renal agenesis is a rare congenital anomaly of the Müllerian duct system referred to as Herlyn-Werner-Wunderlich syndrome. Because of its rare occurrence, a high level of suspicion is often required for diagnosis. Clinically, these patients usually present after menarche with pelvic pain, dysmenorrhea, and a palpable pelvic mass. We present a case of a 31-year-old female patient with infertility. Imaging findings were consistent with Herlyn-Werner-Wunderlich syndrome, with a congenital defect in the longitudinal vaginal septum resulting in partial spontaneous decompression of right-sided hematocolpos.