Changes of paleoclimates and paleoenvironments in the Lake Baikal region (including Transbaikalia and Prebaikalia) are traced through the Late Pleistocene-Holocene on the basis of small mammal faunal succession, the deposit structure and pollen assemblages. Paleoenvironments and biota of the two regions became increasingly different since the end of Middle Pleistocene. In Prebaikalia, tundra-steppe (non-analog) faunas appeared and were dominant through the Late Pleistocene, although there was alternation of faunas indicative of colder and warmer (interglacial) conditions. In the Transbaikalian region, faunas typical of arid landscapes were characteristic of both cold and warm periods. They were similar in the species composition, although differing noticeably in proportion of individual taxa.