Social origins, scale and results of partisan movement on the USSR territory are analyzed. Its national character to defend the Fatherland led to describing this war as the Great Patriotic. The paper discusses basic parameters of partisan formations fighting at the occupied territories of the Russian Federation, Belarus, Ukraine and Baltic republics. Archives of the Central staff of partisan movement permitted to present social characteristics of partisan forces, to demonstrate socio-political and organization factors of the mass partisan movement making, motivations of soviet citizens’ participation in it.