The incidence of gynecologic surgery during the pediatric and adolescent period remains low. In this age group, the causes of gynecologic surgery were usually divided into three parts, congenital anomalies, genital traumas, and pathologic lesions of genital tract including uterine bady and cervix, ovaries, fallopian tubes, vagina, and vulva. Among these, adnexal masses generally have been the most common cause of gynecologic surgery in the pediatric and adolescent patients. Adnexal lesions span a spectrum of pathology from functional (non-neoplastic), benign to highly aggressive malignant neoplasms. The actual incidence of adnexal lesions in the young women is unknown; however, of the ovarian neoplasms operated on during childhood or adolescence, 10-30% are malignant. Therefore, early detection and adequate management of adnexal lesions are prerequisite for the life saving and future preservation of fertility potential. But until now, there have been limited studies regarding the clinical characteristics of patients with adnexal mass during this period, and most studies have been conducted with small numbers of patients. Therefore, more informations regarding the clinical characteristics of patients with adnexal lesions are very important for the early diagnosis and adequate management of the adnexal lesions in children and adolescents.