A case of low-grade endometrial stromal sarcoma resembling ovarian sex-cord tumor in the uterus of a 43-year-old woman is described. This tumor belongs to the group II category of uterine tumors resembling ovarian sex-cord tumor described by Clement and Scully, and the epithelial-like elements show prominent smooth muscle differentiation, proved by immunoreactivity for desmin and actin. The patient did not receive any adjuvant therapy; she is alive and well without recurrence 8 months postoperatively.