Silene erciyesdaghensis Aksoy & Hamzaoglu (Caryophyllaceae) is described and illustrated as a new species from Turkey. It belongs to section Lasiostemones. Its diagnostic characters, description and taxonomic comments are given. Its characteristics are compared with the related Silene olympica. The geographical distributions of the new and related species are mapped. The World Conservation Union (IUCN) threat category and observations on the population are noted. (C) 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158, 730-733.