Pregnancy has a definite influence on the clinical course of certain brain tumors (e.g., cerebral gliomas, prolactinomas, meningiomas, acoustic neuromas) and at the same time brain tumors may affect the course and outcome of pregnancy. These tumors may enlarge during pregnancy and may precipitate raised intracranial pressure or more focal symptoms such as hemiparesis or impaired vision. With the help of the Franklin County Maternal Mortality Study Committee, Barnes and Abbott reviewed the records of all maternal deaths in Franklin County, Ohio, from 1948 through 1957. Of 157,654 live births, there were 170 maternal deaths that occurred during pregnancy, delivery, or up to six months post partum. Thirty-six of these deaths were attributable to complications that primarily involved the central nervous system (21% of all maternal deaths), and in nine (5.3%), intracranial tumors were the cause of death (astrocytoma in three cases, glioblastoma multiforme in two, ependymoma in one, malignant papilloma of the fourth ventricle in one, and meningioma in two). We report the case of a 40-year-old Omani woman in whom a colloid cyst of the anterior third ventricle and internal hydrocephalus developed during the second trimester of her ninth pregnancy. the successful outcome for the mother and baby was related to appropriately timed neurosurgical intervention. We failed to find a report of a similar case in the literature.