This paper deals with the aquatic beetle species of the family Dytiscidae collected from various freshwaters habitats in Montenegro. In total 39 water beetle species were collected from 56 localities in Montenegro between 2007 and 2010. Twelve species and one subspecies are reported for the first time for Montenegro: Agabus sturmii (Gyllenhal, 1808), A. paludosus (Fabricius, 1801), Deronectes moestus inconspectus (Leprieur, 1876), D. platynotus (Germar, 1834), Dytiscus circumcinctus Ahrens, 1811, D. dimidiatus Bergstrдsser, 1778, Hydroporus macedonicus Fery & Pešić, 2006, H. pubescens (Gyllenhal, 1808), Ilybius chalconatus (Panzer, 1797), I. fuliginosus fuliginosus (Fabricius, 1792), I. pseudoneglectus (Franciscolo, 1972), Liopterus haemorrhoidalis (Fabricius, 1787) and Nebrioporus... luctuosus (Aubй, 1838). The female genitalia of Hydroporus macedonicus Fery & Pešić, 2006, a rare water beetle previously known only from southern Macedonia, are illustrated. The present state of knowledge of the Montenegrin diving beetle fauna and its ecological characteristics is discussed.