The article presents the origin and objectives of Soviet policy towards Polish population and the Polish Underground in Polesie during German occupation. On the basis of Soviet documents and Polish literature the author presents changes in Soviet policy: from common operation with the Polish Government in exile imposed by the situation at the eastern front line in 1941-1942, through attempts to treat Poles as allies, to confrontation and decisive actions aiming at the liquidation of the Polish Underground in the subject territory by all possible means. The article includes many new facts excerpted from Soviet archives. Moreover, it emphasizes P.K. Ponomarenko's role in creating anti-Polish policy. It was him who, among other things, recommended denunciating Polish conspirators to Gestapo. The author provides data showing that this suggestion was put into effect. Anti-Polish policy of Soviet authorities in 1939-1941 made Poles and the Polish Underground treat USSR first as an 'ally of our allies' , but after USRR broke off diplomatic relations with Poland in April 1943 and started to liquidate the Polish Underground on the subject territory, as its enemy . The article indicates that also the Belarusian historians take up subjects so far considered controversial and cease to repeat propaganda evaluations of the Soviet historiography.