Five children presented in the first months of life with progressive megalencephaly and leukodystrophy characterized by diffuse swelling of the white matter, cystic cavitations in frontal and temporal lobes, and a slow progressive course contrasting with the intensity of the leukodystrophic process. Four had epilepsy. Two were brothers and three had consanguineous parents. No metabolic defect was detected. The clinical and magnetic resonance imaging features are similar to those of patients previously reported. These five new cases add arguments to delineate a new type of leukodystrophy with megalencephaly in infancy and autosomal recessive inheritance.