ENThe article deals with the identification criteria of the Polonisms and Belarusianisms (of the different period of time) borrowed in Lithuanian. Due to the analysis suggested here, Polonisms and Belarusianisms of the Lithuanian language are to be codified under the following criteria: 1) by virtue of the formal usage, i. e. in accordance with the identical morphological and semantic status of the lexemes of Polish and Belarusian origin; 2) on the basis of structural conformity / discrepancy; 3) by means of semantic congruity / contrariety.