Three patients with neonatal thrombosis of the middle cerebral artery are described. In two patients the thrombosis was secondary to neonatal asphyxia. The third patient had a porencephalic cyst twenty days after birth suggesting a prenatal origin of the thrombotic event. The follow-up was carried out for two years. In the first year, two patients had infantile spasms and hyparrhythmic pattern of EEG. This type of epilepsy has never been previously reported. Futhermore, all three patients presented hemiplegia and reduction of cranial circumference. The neuroradiologic procedures showed to be very useful for the diagnosis and long term follow-up. These patients must be followed carefully since the development of a subsequent epilepsy is reported to be approx 11%.