The abundance dynamics of the five massive species of fleas (Frontopsylla elatoides elatoides Wagner, 1928, Oropsylla alaskensis (Baker, 1904), Rhadinopsylla li transbaikalica Ioff et Tiflov, 1947, Neopsylla mana Wagner, 1927 and Frontopsylla hetera Wagner) on Siberian ground squirrel in the Kargy river valley during 1964–2013 have been analyzed. Close correlation between number dynamics of these species with climatic changes during this period have been revealed. Peak abundance of hygrophilous species was timed to period of 80 s–beginning of the 90 s. Sharp rise of xerophilous species numbers and increasing of all species migration activity were observed since the late 90 s with peak at 2004–2008 when the climate was the most arid. The reproduction of generation of this year is the probable reason of Frontopsylla elatoides number increasing.