ABSTRACT The genus Bostryx Troschel, 1847 is found exclusively in South America, from Ecuador to Chile and mainly in the Andes mountain range. The phylogeny of Argentinian species of Bostryx was based on morphological characters of 19 species from Argentina, 5 from Peru and 7 from Bostryx-related genera, belonging to Bulimulidae and Odontostomidae. A matrix of 31 taxa and 78 morphological characters (19 of which were continuous and 59 discrete) from shell, pallial and reproductive systems was analysed under implied weighting with TNT. Argentinian species of the genus formed a monophyletic group together with the Peruvian species. The monophyly of this clade was supported by a set of 14 synapomorphies, principally related to continuous characters of the shell shape.