Inland water crustaceans in Chile are characterized by their low species number and marked endemism; this is due to the marked oligotrophy of water bodies and the geographical properties of Chilean territory, which consists of mountains and glaciers. The aim of the present study is to typify the inland water crustaceans in the northern Aysen region (44-46°S), which is branded by the presence of mountains, ice fields and inland seas, with different kinds of water bodies such as large lakes, permanent and ephemeral pools, rivers and streams. The results revealed low species numbers, but the species associations are random, because in many sites the same species frequently reoccur. Nevertheless, there are marked differences in species associations. The present results tend to agree with similar results for the Magallanes region in southern Patagonia and Argentinean Patagonia.