The aim of the article is discussion of influence of the Polish language on Latvian dialects in the area of Latgale. The close contiguity as well as genetic nearness of the Polish, Belorussian and Russian languages makes it difficult to state categorically which of them was a direct source for Latvian. Knowledge of settlement in the area of Latvia does not facilitate this task as these three Slavonic nations considerably reinforced former Livonia and Courland. The material basis of the discussion constitute two studies - dialectal atlas of Latvian 'Latviesu valodas dialektu atlants' and dialectal texts from Latgale 'Augszemnieku dialekta tekst. Latgaliskas izloksnes'. The article presents analysis of names which may have appeared in Latvian dialects from Polish. Polish (as well as Belorussian or Russian) could have equivalently affected the range of lexical Latgalian dialects and neighbouring dialectal groups. These are 'bocjans' (stork), 'butelka' (bottle), koldra (quilt), mjantuzs, mentuzs (burbot - kind of fish), skvarkas (crackling). A separate group is formed by names for which the Polish language (or other Slavonic languages) was a medium for borrowing words of German origin: 'cegla' (brick), kartufelis (potato), 'skuoda' (place in a field damaged by animals), 'selma' (knave), 'svagars' (brother in law). Among Slavonic words there are such words with which it is impossible to decide on the direction of borrowing because of similarity of forms and common proto-Slavonic source: 'malina' (raspberry), 'sawa' (owl), 'zapaks' (smell). The source of polonisms in Latvian dialects were words belonging to general Polish. Therefore the argument about considerable influence of Poles who represent higher social strata seems to be confirmed. Moreover one can indicate that Polish North-Eastern dialect of the Polish borderland must have affected Latgalian dialects however it is difficult to indicate to what extent.