Objective 
Ovarian mature teratoma (OMT) is a common ovarian tumor found in the pediatric population. In 10% to 20% of cases, OMT occurs as multiple synchronous or metachronous lesions on ipsi- or contralateral ovaries. Ovarian sparing surgery (OSS) is recommended to preserve fertility, but total oophorectomy (TO) is still performed. This study reviews the clinical data of patients with OMT, and analyzes risk factors for second events.