Words of Slavonic origin are both characteristic literal language phenomena (Laua, 1981) as well as phenomena of Latvian language sub-dialects. Especially frequent they are in Latgalian sub-dialects and they are only sporadically met in other places in Latvia (Laumane, 1977, 55). The aim of this article is to analyze words of Slavonic origin in one of Latvia’s South West sub-dialects – Rucava sub-dialect, their frequency in the neighboring sub-dialects of Rucava, to analyze them from the point of view of word class as well as to look at thematic groups of words of Slavonic origin. There are not observed a large number of words of Slavonic origin in Rucava’s sub dialect. It is also problematic to define their origin since many of them might have been borrowed in through Lithuanian language from the Polish or Russian languages (Lau mane, 1977, 55–56) One of the important issues connected to words of Slavonic origin is the problem of chronology. For example, part of these words used in Latgalia has ancient roots (Laumane, 1977, 50-51, 55-56). Whereas part of Slavonic words used in South West Kurland’s sub-dia lects might be of newer origin because there are no direct historical contacts with Slavonic languages or sub-dialects. Thus the question: are they direct or indirect borrowings? Sometimes it is difficult to trace from which language or even from which language group the lexemes have been borrowed: From Russian or Polish: for example irka – “decorative embroidery on the sleeves of a shirt”; kuds – “slim, thin, skinny”; slīve - ”plum” and others; From Slavonic or Germanic languages, for example, gruce – “borridge made of barley, pearl-barley”; jāmarks/jāmarka – “fair”. From the aspect of geographical distribution a few lexemes have been observed only in Rucava and neighboring sub-dialects (such as lexemes gvazdiks, jāmarks); part of lexemes are mostly spread in Latgalia, sometimes also in other places of Latvia (for ex ample, durns, kavat, kuska). In the collected material there are 74,4% nouns, 15,4% verbs, 7,7 % adjectives and 2,6% adverbs. 144 Thematically 15,4% lexemes denote actions and names of plants, 12,8% lexemes are connected to clothing, 10,3 % lexemes are connected to household life andothers. As to the territorial aspect – some lexemes so far have been observed only in Rucava and the neighboring sub-dialects (suc as lexemes gvazdiks, jāmarks, piegrazāt); some lexemes typical for Rucava most often are observed in Latgalia, sometimes in other places of Latvia (for example, durns, kavāt, kuska). Rucava’s sub- dialect words of Slavonic origin have been actively used in the late 20th century and at the beginning of the 21st century. Some of the Slavonic borrowings still have phonetical and morphological variants as well as various derivatives (for example, kuds//kuts; riedīt//izriedīt//pieriedīt), thus proving their vitality also in the future.