A new species of entomopathogenic nematode, Steinernema vulcanicum n. sp., is described from the slopes of Mount Etna (Sicily, Italy). It was recovered from soil in a chestnut wood. Molecular and morphological data indicate that the new species belongs to the glaseri group of Steinernema spp. The new species can be distinguished from the other described species of the group by morphological characteristics, crossbreeding tests and by the DNA sequences of ITS1 rDNA, 12S and cox1 mitochondrial loci. Steinernema vulcanicum n. sp. is characterised by the long and slender male spicules, with manubrium wider than long, velum prominent, rounded tip with ventral concavity and tail without mucro. The female has double epiptygmata in both generations. The third-stage infective juveniles have an average body length of 1200 μm, excretory pore generally located level with posterior part of the pharyngeal corpus (D% = 47-68), lateral field pattern of variable formula and hyaline part of tail forming ca 50% of its length. The DNA sequences, life cycle and the endosymbiotic bacterium of S. vulcanicum n. sp., Xenorhabdus kozodoii, indicate the similarity of the new species with S. arenarium, S. apuliae and S. boemarei, from which it can be distinguished by both morphological and molecular characters.