In this study, 17 species belonging to the genus Stenus Latreille, 1796 (Staphylinidae: Steninae) were determined in Ankara province. Examination material is composed of samples which were collected between May-September 2003, May-September 2008 and April-June 2009. 13 of these species are the first records for Ankara. Genitalia of 15 species, of which males found, were drawn in detail and according to references we have, genitalia of two species, S. turbulentus Bondroit, 1912 and S. turcicus Bernhauer, 1912, were drawn for the first time. Additionally, entire structure of median lobe of 3 species, Stenus affaber Baudi, 1848, S. bicornis Puthz, 1972a and S. callidus Baudi, 1848; sclerites and parameral setae of five species, Stenus affaber Baudi, 1848, S. argutus Puthz, 1972, S. bicornis Puthz, 1972, S. callidus Baudi, 1848 and S. cordatoides Puthz, 1972 and clasp structures of three species, S. argutus Puthz, 1972, S. bicornis Puthz, 1972 and S. cordatoides Puthz, 1972 were drawn for the first time. Furthermore, in this study male genital structure key was prepared for 15 species first time.