This work is the first to comprehensively examine the phraseological systems of the Bulgarian and Romanian languages, based on the most complete factual documentation possible. Phraseology is usually defined as the most specific and therefore most difficult to translate part of the expressive richness of any language. Comparative typological research contributes to the discovery of its actual specificities in a given language, as well as cases of similarity, closeness, resemblance, and difference. The book is the first part of a multifaceted study of the phraseology of two languages belonging to different language families but developed within the Balkan language community. It analyzes the phraseological material in terms of the components and structural organization of phraseological units, while also highlighting a number of grammatical issues that are directly reflected in them. It shows the characteristics of form in their close connection with the types of semantics in phraseology. The book is intended for philologists, translators, Bulgarian students majoring in Romanian philology and Balkan studies, Romanian students studying Bulgarian philology, as well as anyone interested in the problems of phraseology.