Malignant mixed germ cell tumors,though rare overall, are the most common type of malignant ovarian neoplasms in young and adolescent girls. These tumors are rapidly growing and can metastasize. We report a case of 13-yr-old girl who presented at SHKM GMC, Nalhar, Mewat, Haryana, India in December 2013 with huge abdominal lump of a malignant mixed germ cell tumor comprising both immature teratoma and embryonal carcinoma. This report illustrates the aggressiveness of this tumor and emphasises the need of early diagnosis and treatment.