Hatem NAJAR 2-Dimensional localization of acoustic waves in random perturbation of periodic media. (414K, DVI and PDF files) ABSTRACT. In this work we study internal band edges localization of acoustic waves in 2-dimensional space obtained by random perturbation of some periodic media. Our results rely on the study of Lifshitz tails for the integrated density of states for random acoustic operators of the form $A_{\omega}=-\nabla\frac{1}{\varrho_{\omega}}\nabla$. Localization is then deduced by the standard multiscale argument.