Theoretical contrastive studies The contrastive studies criticism in the 60s – 70s of the 20th century was the only basis for quite a few researchers to formulate their opinion on the studies. Although the criticism is becoming out-of date, it has not lost its inertia to disapprovingly dispose to and discourage from contrastive studies. It should be emphasized that the contrastive studies have taken quite a different course since then. The key charge of the lack of a solid basis for the combination of the languages is no longer in effect. The contrastive studies guidelines formed from scratch by the Semantics Research team of the Institute of Slavic Studies of the Polish Academy of Sciences are evidence for it, successfully finding their application in previously published multi-volume monographs (Koseska, Penčev 1988-2009, Korytkowska, Koseska, Roszko 2007), a number of works of the authorship of S. Karolak, M. Korytkowska, V. Koseska, V. Maldjieva, D. Roszko, R. Roszko and others (compare the bibliography in Korytkowska, Koseska, Roszko 2007), as well as in the Polish-Lithuanian Contrastive Grammar in preparation by D. Roszko, R. Roszko. The fundamental principle of the contrastive studies is orienting the studies from the semantic ground (the interlanguage) to the formal ground. Using the interlanguage as a semantic tertium comparationis creates a solid and explicit basis for the combination of the languages. The bases for theoretical contrastive studies have come into existence at the Institute of Slavic Studies. Therefore, the guidelines for them were applied for the contrast of Slavonic languages (mainly Polish and Bulgarian). Afterwards, the Lithuanian language, belonging to the Baltic languages, was included among the languages being contrasted. It is noticeable that the studies itself and the published works based on the criteria of theoretical contrastive studies refer to less popular and poorly spread languages, that is Polish, Bulgarian and Lithuanian. Moreover, for quite a time the majority of these works were published mainly in Polish and Bulgarian. Despite a few decades of the existence of the new linguistic contrastive method, the above-mentioned facts caused that the method isn’t well-known. The idea of this article is to make the researchers get interested in the guidelines for theoretical contrastive studies and the results of some of the linguistic contrasts carried out until now.