Klippel–Trenaunay syndrome (KTS) is characterized by localized vascular naevus, congenital or early infantile varicosities, and soft tissue or bony hypertrophy. It was been described to be associated with hemimegalencephaly and Chiari I malformation in isolation. Here we present a case of a child who presented with KTS associated with both hemimegalencephaly and Chiari I malformation. The clinical presentation of the child and the likely pathogenesis of association with Chiari I malformation in KTS are discussed. The overall management of KTS with Chiari 1 malformation is reviewed.