This report describes a case of megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome in a 1-year-old boy, born to healthy nonconsanguineous parents. Megalencephaly and bilateral postaxial polydactyly of upper and lower limbs were noted at birth. He had profound developmental delay and moderate hypotonia. Magnetic resonance imaging (MRI) of the brain revealed hydrocephalus, polymicrogyria in both frontal lobes and perisylvian regions, and thin corpus callosum. Array-comparative genomic hybridization was normal. The patient's clinical and radiologic findings fit the classic description of megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome. The possible overlap between megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome and other similar conditions is discussed.