Granulosa-stromal tumors comprise 5 to 8% of all primary ovarian neoplasms. The first clinical manifestation is precocious puberty in most prepuberal patients. We report a case of mixed germ cell-cord stromal tumor of ovary in a 7.2 years old girl, who presented with isosexual pseudo-precocious puberty of progressive outcome. Serum testosterone, estradiol and 17alphaOH-progesterone levels were increased. Abdominal-pelvic ultrasound revealed a right ovarian mass. Unilateral salpingo-oophorectomy was performed with complete resection of the tumor. The patient is well 7 years after surgery with normal pubertal and growth development and no signs of tumor relapse. We review the clinical manifestations of ovarian tumors, classification and staging of sex cord-stromal tumors, follow-up, tumor markers, treatment and prognosis.