The neurological outcome for severe toxoplasmosis can be poor despite appropriate management.A maternal toxoplasma infection occurred at 16 weeks of amenorrhoea; prenatal diagnosis was attempted at 20 weeks, fetal infection was confirmed by mouse inoculation at the 30th week. Pyrimethamine plus sulfadiazine treatment was initiated. However, at 37 weeks of amenorrhoea, sonographic examination of the fetus detected hydrocephalus. Despite prompt ventriculo-peritoneal shunting after birth and medical treatment of toxoplasmosis, the neurological developmental outcome was complicated and prognosis is poor at 5 years of age.This case shows that parents must be carefully warned about risks of a prenatal toxoplasmosis.