In this article quantitative and spatial dynamics of Russians of modern Kazakhstan whose number during the Post-Soviet period was reduced almost by 40% is investigated (from 6,1 to 3,6 million people). The main part in this process was played by migration which share was about 85-90% of all demographic losses of the Russian community during the Post-Soviet period. The decrease of Russians was widespread. But in the 1990th the Russian population of the southern and western areas of Kazakhstan was reduced with priority rates. At the beginning of the XXI century rates of depopulation of Russians from different regions of the country were considerably leveled off. In addition, migration scales were multiply reduced. However, nowadays they amount to 15-20 thousand people a year, remaining the central factor of reduction of the Russian community. During the Post-Soviet period Russians of Kazakhstan were the second (after Kazakhs) epicenter of ethnic consolidation of other people of the country, assimilating part of representatives of Russian-speaking diasporas and in such a way partially compensating the demographic losses. However, so far this resource of replenishment is substantially exhausted. Scales of migration and specific variant of their natural reproduction will define further quantitative dynamics of Russians. Depending on a combination of options of mechanical and natural losses, the general scale of losses of Russians of Kazakhstan during 2016-2050 can amount from 500 thousand to 1,8 million people. The most probable range - 0,85-1,2 million. Despite such considerable losses the Russian community of Kazakhstan by the middle of the century involving 2,45-2,8 million people, with a high probability will become the largest center of the Russian population outside the Russian Federation, bypassing Ukraine in this quality. At the same time the share of people older than 70 years among Russians of Kazakhstan during 2011 -2050 even without migration of youth can grow from 9,3% to 20% (and taking into account outflow it will amount to 25% or more). Moreover, to accruing aging of representatives of the Russian community capable since a certain moment sharply accelerate scales of its natural losses will constitute the greatest demographic danger in the second to half of the XXI century.