The paper presents the problem of transformations of phraseological units in modern Russian and Slovak advertising slogans. The primary task of the advertising slogan is to attract the attention of the recipient, to interest a potential buyer, to motivate him to buy certain products. When classical linguistic means and techniques turn out to be ineffective or outdated, the creators of advertising slogans resort to various transformations of the existing material well-known to a certain society, word play and other experiments with language. Transformation of phraseological units is a justified, effective and highly relevant method of attracting attention in various spheres of communication (media, fiction, Internet, blogs, advertising, politics, etc.). This technique has occupied the dominant position in advertising for more than a decade, since fixed expressions or allusions to them appeal to the wisdom of the nation, its origins, and evoke positive images in memory. The purpose of this article is to identify the transformations of phraseological units in advertising using the example of two Slavic languages, to analyse specific examples of transformations created by Russian and Slovak authors, to consider the methods of creating such transformations, to note their features and to draw appropriate conclusions.