In this report, we describe ovarian mixed germ cell tumor in a patient with Turner syndrome. Right ovary was replaced by a 15 x 11 x 10cm teratomatous benign tissue and small area of mixed malignant germ cell tissue. The malignant germ cell portion was composed of embryonal carcinoma and loose reticular area of yolk sac tumor and syncytiotrophoblastic giant cells. Left ovary was streak gonad. This is the first reported case of mixed germ cell tumor with Turner syndrome in Korea.