A 56-year-old woman had complained of two year's consecutive left-side abdominal pain. Retroperitoneal tumor was diagnosed and the patient was referred to our institute in December 2014. Laboratory data including endocrinological activity and serological markers were within the normal ranges. Imaging studies showed that the solid tumor measuring 5 cm in diameter was uncovered in the retroperitoneum, between the abdominal aorta and left kidney. The patient underwent surgical removal of the tumor with the left kidney because the mass was highly adhesive to the left ovarian vessels and left renal vein. Histological examination showed proliferating spindle cells in the tumor, and immunoreactivity for desmin and alfa-smooth muscle actin in tumor cells confirmed the diagnosis of leiomyosarcoma originated in left ovarian vein with left renal vein invasion. The patient has been free of disease 21 months after the surgery. Ovarian vein leiomyosarcoma is extremely rare and we have found 18 cases in literature. Furthermore, only three cases of leiomyosarcoma arising from the ovarian vein with the renal vein invasion were reported including our case.