Teratoma is a rare tumor of the central nervous system that belongs to intracranial germ cell tumors. We report a 2-month-old male child with an immature teratoma of the posterior fossa. Physical and laboratory examinations were normal. Though a radiologic examination was characteristic for this neoplasm, it was insufficient to make a definite diagnosis. Combining the radiologic findings with a histopathologic examination contributed to diagnosing immature teratoma and differentiating it from other subtypes of intracranial germ cell tumors. Our aim was to provide a greater understanding of immature teratoma by reporting this case.