The most common site of the teratoma in infant and children is sacrococcygeal region, but is rare tumor with incidence of one in 20,000-40,000 birth. It rests anatomically behind the rectum and anterior to the sacrum, and usually has an external portion of variable size. The tumor occurs predominantly in females and appears to be associated frequently with twins, family history of twinning, or malformation. Usually the sacrococcygeal teratoma has a benign fashion in neonate, but there is a definite propensity to undergo malignant change, usually after 4 months of life. We have experienced a case of malignant sacrococcygeal teratoma in 27 weeks old girl who was died in maternal uterus. The mass, 830gm in weight, discloses variable degrees of differentiation of teratoma with malignant foci in histologic examination.