Familial cases of Chiari malformation with syringomyelia are rare. The majority of the reported series and case reports detail sporadic cases. The authors report two siblings who presented with Chiari type I malformation and syringomyelia (CMI+S). We report two sisters who each presented with scoliosis on routine school physicals. Their clinical examination was unremarkable; however, imaging studies demonstrated a Chiari malformation with syringomyelia. Both underwent cervicomedullary decompression, and follow-up imaging studies revealed resolution of the syringomyelia. A review of the literature reveals fewer than ten previous reports of familial CMI+S in the past 30 years. Although rare, the existence of familial cases of CMI+S suggests a genetic component to the pathogenesis of this condition in at least a proportion of patients. Neurosurgeons should be aware of the familial aggregation of CMI+S.