A leiomyosarcoma that occurred in the right kidney with hepatic metastasis of a 15-year-old intact female Asian water buffalo (Bubalus arnee) in a zoo, Republic of Korea. The animal showed no clinical signs. Grossly, a firm and white mass (6.0 x- 5.0- x 4.0 cm) was observed in the renal capsule and multiple firm white nodules, measuring 1.0-2.5 cm, were present on the surface of the liver. Microscopically, tumor cells were spindle-shaped, the cell density was high, and complex fasciculated tumor cells showing longitudinal and transverse cross-sections were observed. Tumor cell nuclei was ordinarily cigar shaped and had rounded blunt ends. Immunohistochemically, tumor cells reacted intensely with anti-smooth muscle actin antibody. This is the first case report of a renal leiomyosarcoma with hepatic metastasis in a Asian water buffalo.