Uterus didelphys, a mullerian anomaly, coincidental with renal agenesis and unilateral imperforated hymen is extremely rare. It mostly presents with cyclical abdominal pain, dysmenorrhea or the feeling of abdominal mass. In this report, a case of uterus didelphys regularly menstruating from the left side and suffering from cyclical abdominal pain due to hematocolpos and hematometra because of imperforated hymen on the right side is presented. Fifteen-year-old girl was admitted to the emergency service with the symptoms of dysmenorrhea and abdominal mass. Her medical history revealed chronic abdominal pain and right renal agenesis. Laboratory tests were normal. Ultrasonographic examination revealed a tubular cystic mass. Magnetic resonance imaging demonstrated that uterin didelphys and duplicated vagina with right hematocolpos and hematometra. Imperforated hymen on the right hemivagina was confirmed by pelvic inspection. We performed an incision on longitudinal unilateral septum using a fine scalpel without any hymenal damage, and thereafter 400 ml hematoma was drained. Vaginal septum was resected completely via linear surgical stapler. Symptoms disappeared during follow up, and after two months, the didelphic uterus was clearly seen on transabdominal ultrasonography. Mullerian anomalies should be suspected in recently menstruating patients who present with dysmenorrhea.