Abstract Ostracoda are small entomostracan Crustacea that are abundant in marine and nonmarine aquatic environments and that are excellent microfossils in paleoenvironmentalreconstruction (Whatley, 1983, 1988).They are extensively employed in this role in Quaternarynonmarine environments (Whatley, 1983;Aguirre and Whatley, 1995).In this paper, we present a review of studies of late Quaternary lacustrine ostracods from northern Patagonia, based on the analysis of numerous samples from lake bed cores and from outcrops along an approximately west-east transect near Mount Tronador (lat.41 00'S; long. 71 50'W) to Lake Cari-Laufquen (lat.41 12'S; long. 69 25'W). This transect has been the subject of a multidisciplinary study called the Lagos ComahueProject, which has the objective of contributing to our knowledge of the evolution of the climate, the environment, and the biota from the late Pleistocene through the Holocene of the cordilleran and patagonianmarginal areas as part of our understanding of global change. There is a large and growing body of literature on the Ostracoda of Argentina, but only a small part ofthis work is devoted to the ostracods of Quaternarylake deposits. Among such papers are those by Daday(1902), Ramirez (1967), Whatley and Cholich (1974),Zabert (1981), Zabert and Herbst (1986), Bertels andMartinez (1990), Aguirre and Whatley (1995), Cusminsky(1994, 1995), Cusminsky and Whatley (1995,1996),and Whatley and Cusminsky (1995a, b).