The article presents 'Baltisms' present in the 'Dictionary of Knyszyn Dialect' (not yet in print), in the collection comprising more than 5 500 words recorded by Czeslaw Kudzinowski during several decades (of the first half of the 20th century). The town of Knyszyn is situated close to the zone of Lithuanian dialects (in the North) and the Easter Slavonic dialects (in the East). Its Western border touches the Mazowsze region. The analysis involved words which are considered undoubtedly to be the words borrowed from the Lithuanian language. Those were: 'bonda' (a bread loaf), 'brejtac' (to meddle, complicate), dersac' (on a cart on a bumpy, uneven country road: to bump), 'dulki' (a dust produced by crops handled in barn), 'genac' (to cut off the side shoots from a withe), 'jegla' (a fir-tree), 'kizuk' (a foal), 'krusna' (a mound of stones collected from a ploughed field at its side), 'kulsa' (a hip), 'kump' (a ham), 'kumsci' (handful of something), 'kursac' (incite, push), 'lupa' (a lip), 'musy' (lees), 'tosa' (a metal bar connecting a shaft with the cart axle), 'pakule' (tow), 'posor' (litter), 'rojst' (marsh), 'sakal' (a wood log), 'spyl', 'spel' (splinter), 'sfiren' (a granary), 'spurc' (a kid, urchin), 'zagar'. Most of the words mentioned here were noted to appear in a broader area, and are common for the area of the former Grand Duchy of Lithuania, and thus appear in the Polish, Belarussian and sometimes in Ukrainian dialects, as well as in Central Great Russian dialects of the Western Strip.