This paper explores the modes of dispersal, variability and chronology of the Initial Upper Paleolithic (IUP) of Southern Siberia and the northern Central Asia. Several types of tool-markers, a peculiar type of reduction technology and two types of adornments, specific to the area under study, are distinguished. Based on the current data, the author concludes that about 45,000 years ago, there was a rapid eastern movement of populations from the core region in part of the mountains of the Russian Altai to central Mongolia and southwestern Transbaikal area. In these regions about 43000–40000 BP, the second center of a blade-based IUP appeared. It was characterized by specific forms of tools, reduction technologies and personal adornments similar to those in the core region. Thus, the transfer of a whole set of common cultural traditions occurred. Therefore, judging by geographic and temporal distribution of toolmarkers, ancient populations moved along the extreme southern route, i.e. over the territory of today’s Mongolia and north-western China.