Sertoli-Leydig cell tumor is a rare sex-cord stromal tumor of the ovary. They make up less than 0.5 % of all ovarian tumors. We experienced a case of an ovarian Sertoli-Leydig cell tumor in a 4 year-old girl who presented with nausea, vomiting, and lower abdominal pain of 2 days' duration. On physical examination, there was mild tenderness in the right lower quadrant of the abdomen. Abdominal ultrasonography and computed tomography (CT) scan revealed a pelvic mass measuring 5 x 3 cm that appeared to arise from the right ovary. At exploratory laparotomy, a 6 x 5 x 3 cm solid right ovarian mass without torsion was found. A right salpingo-oophorectomy was performed. The postoperative course was uneventful. The child was discharged 5 days after surgery.