Lake Issyk-Kul is the seventh deepest lake in the world situated inCentral Asiain theTien-ShanMountainsat the elevation of 1607 m above sea level. This area belongs toKyrgyzstan. From 1927 to 1997 the water level decreased by 3.4 m, and increased by 0.93 m from 1997 to 2011. The article analyzes the impact of the global warming on the Lake Issyk-Kul thermal regime and the components of its water balance: river discharge, precipitation, evaporation and lake level variations. It shows that the global warming has entailed the increase of the Lake Issyk-Kul water temperature down to the maximum depths, and river discharge increase due to the glaciers melting and the evaporation from the lake surface. The air temperature increase of 1 ℃ results in river discharge increas and lake level rise of 44 mm/year and surface evaporation increase of 88 mm/year. TheLakeIssyk-Kullevel increase after 1997, which takes place in the situation of global warming, was caused by the activation of the West air masses transport and increase of precipitation in autumn.