During fetal development, abnormalities during Mullerian duct formation can lead to varied types of uterine, cervical, or vaginal anomalies. Herlyn-Werner-Wunderlich Syndrome (HWWS) is a rare, congenital Mullerian duct anomaly characterized by the triad of uterine didelphys, obstructed hemi-vagina, and ipsilateral renal agenesis. If the diagnosis is delayed or missed, permanent sequalae such as chronic pain, infection, and infertility can result. This is a case of a 16-year-old woman with heavy vaginal bleeding and menstrual cramping in which sonography was used in the diagnosis of HWWS. Sonography plays a vital role in this diagnosis, as it is the most common initial imaging examination. For this reason, it is important that the characteristics of uterine anomalies, like HWWS, be recognized with sonography. It is important that this diagnosis is made early and treatment can be initiated to prevent irreversible complications.