In 2007, 2008 and 2009 the authors carried out an extensive study of the amphibian and reptile fauna of the island of Mljet resulting in the detection of 12 species. One amphibian and 11 reptile species were recorded (Emys orbicularis, Testudo hermanni; Hemidactylus turcicus, Podarcis melisellensis, Dalmatolacerta oxycephala, Pseudopus apodus; Coronella austriaca, Hierophis gemonensis, Zamenis longissimus, Malpolon insignitus and Vipera ammodytes). In addition, previous publications reported findings of Bulb viridis, Anguis Elaphe quatuorlineata and Zamenis Made. Lacerta agilis and Podarcis siculus were obviously mentioned erroneously. With a total of 16 species, the island of Mljet is of average herpetofaunal richness among Mediterranean islands but one of the richest Adriatic islands. Four species are listed in the Red Data Book of endangered amphibians and reptiles of Croatia: Caretta caretta as endangered (EN), Emys orbicularis and Testudo hermanni as near threatened (NT), and Zamenis situla as data deficient (DD).