We report a case of spontaneous retroperitoneal hemorrhage caused by rupture of an aneurysm of the right ovarian artery in a 55-year-old woman. Diagnosis was achieved by computed tomography and arteriography. The ruptured aneurysm was treated by transcatheter arterial embolization using microcoils and gelatin sponge particles. This is the first case of rupture of an aneurysm of the ovarian artery not related to pregnancy, and the third case of embolization of a ruptured ovarian artery aneurysm in the literature. We illustrate the usefulness of embolization in treatment of an ovarian artery aneurysm without surgery.