A contribution to the knowledge of the Turkish water beetles fauna (Coleoptera)Abstract : A total of 28 species of water beetles were collected from 11 sampling stations in the semiarid central Turkey (Aksaray, Kırşehir and Konya provinces) between 2004 and 2005. They belong to the following families (species numbers in parentheses): Gyrinidae (4), Haliplidae (2), Noteridae (1), Dytiscidae (9), Helophoridae (4) and Hydrophilidae (8). One species of Dytiscidae [Oreodytes septentrionalis (Gyllenhal, 1826)] and two species of Hydrophilidae [Enochrus (Enochrus) melanocephalus (Olivier, 1792), Enochrus (Lumetus) fuscipennis (Thomson, 1884)] are reported from Turkey for the second time. Also ten new records are added for the Coleoptera fauna of the Central Anatolia region with this study. For some remarkable species phenologies, habitats and additional distributional notes are given.