Placental teratoma is a very rare tumor. The tumor we present that lay between amnion and chorion contained disorganized skin and its appendages, bone, cartilage, and fat. There was no evidence of recognizable umblical cord. Our diagnosis was “mature teratoma of the placenta”. The distinction between teratoma and fetus acardius amorphus, besides the possible origin of a tumor in this site, is discussed with a brief of literature.