We report a case of congenital cerebral glioblastoma. The initial antenatal ultrasound scan showed a peripheral area of high reflectivity within the right cerebral hemisphere. A subsequent scan showed that the area of high reflectivity had increased in size to completely fill the hemisphere, with shift of the falx and contralateral ventriculomegaly. Glioblastoma is one of the least common congenital brain tumours and has the poorest prognosis with no recorded cases surviving beyond one year.