OHVIRA syndrome: Uterus didelphys with an oblique vaginal septum that causes partial genital tract outflow obstruction and a urinary tract anomaly. Malignancies are rare, with early literature documenting only a handful of cases—historically categorized almost exclusively as cervical cancers. Recent reviews highlight a slightly broader spectrum of lower genital tract involvement. To our knowledge, aggressive histologies such as carcinosarcoma (mixed Mullerian tumor) in an OHVIRA patient have never been previously reported in the global literature. Our patient—42 yr old, divorced, nulligravida, with a history of drainage of hematocolpos + marsupialization of hemivagina at the age of 28 years. The patient was diagnosed with Uterus didelphys with a non-communicating horn with hematosalpinx along with ipsilateral renal agenesis and managed surgically. She presented with persistent mid-menstrual blackish vaginal bleeding. Initial pelvic examination revealed foul-smelling discharge and a mass arising from the cervix. MRI pelvis showed a distended vaginal cavity with a large polypoidal mass extending toward the left cervical cavity. PET scan showed a hypermetabolic polypoidal mass arising from the uterine cervix extending into the vagina. Excision of mass was done, which involved the anterior and lateral walls of the cervix. Histopathology report was suggestive of carcinosarcoma of the vagina (syn—mixed Mullerian tumor). A radical hysterectomy with sos pelvic lymph node dissection was planned. On the table, the tumor was inoperable with no discernible plane of dissection extending up to the introitus. The patient is now undergoing chemotherapy with taxanes. Our case is unique, being a vaginal carcinosarcoma in a Mullerian anomaly with an aggressive course.