Dyke-Davidoff-Masson Syndrome (DDMS) is a rare condition characterized by asymmetry of cerebral hemispheric growth with atrophy on one side, ipsilateral compensatory osseous hypertrophy, and contralateral hemiparesis. We experienced a 17 month-old male who presented with left focal clonic or tonic-clonic seizures accompanied by left hemiparesis and developmental delay. Brain MRIs demonstrated progressive atrophy of the right cerebral hemisphere with dilatation of the lateral ventricle, expansion of the ipsilateral frontal sinus with calvarial thickening, and elevation of the petrous pyramid and orbital roof. Brain SPECT showed a decreased volume of the right hemisphere with reduced blood flow. We therefore report a case of DDMS with a review of the literature.