In this article the author describes a lower jaw of a fossil proboscid, Gomphotherium angustidens, which lived during the Miocene. The material originates from Hungary. Apart from the description of the morphological characteristics of the lower jaw, the living environment of this Mastodont is reconstructed based upon materials from museums. The evolutionary history of proboscids is described with special emphasis on the extinction of Gomphotherium angustidens.