Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare, recently described disease. It is characterized clinically by a large head, mild neurological symptoms and a remarkably slow course of functional deterioration. The MRI is characterized by 'swollen white matter' and large symmetrical cystic changes in the cerebral hemispheres. MLC should be considered in the differential diagnosis of children with megalencephaly and leukoencephalopathy. We report a child with this disease and discuss the MRI and MRS features.