EN
The article presents unusual plural forms of nouns excerpted from various publications printed in Polish in Republic of Lithuania (the years 1919−1940). The changes of grammatical number are not so typical for the studied language as changes of grammatical gender, but they also are worth attention of lin-guists. Characteristic changes of a number may be observed mostly in Polish influenced by Lithuanian. The most common are uses of plural instead of singular. In the group of 72 unusual grammatical forms 51 nouns were used in plural. Most of these uses (75%, 38 examples) has Lithuanian origin, which dif-fers from Polish in a way that different classes of nouns function as pluralia tantumand some of Polish singularia tantummay inflect for number.