Massive congenital intracranial teratoma (MCIT) is a very rare tumor and only one case has been reported in Korea. We report a case of MCIT discovered in a male infant of 25 weeks of gestational age. Prenatal ultrasound revealed a large heterogenous echoic mass which almost replaced the intracranial content. The infant was severely macrocephalic with a small but normal appearing body. The cranial vault was almost entirely occupied by an 18cm sized, multilobulated, partially cystic mass that displaced the severely distorted and attenuated cerebral cortex. Microscopically, the bulk of the tumor was composed of embryonal neuroepithelium with mature glial tissue and choroid plexus. Cartilage, liver, mature squamous epithelium and differentiated mesenchymal elements such as muscle and adipose tissue were found within the tumor.