The article examines the reasons of formation of enantiosemy in modern Bulgarian. They are divided into extralinguistic and linguistic depending on their nature. The features of the primitive thinking, the aspiration for nonstandard expression of thougths, the cultural-historical factors belong to the first group. The second group consists of such factors as opposite meanings of word-formative affixes, morphological word-formation irrespective of meanings of derivational morphemes, lexico-semantic induction in paradigmatic and sintagmatic respect, phonetic changes. The article points out their role on the formation of enantiosemic language items in Bulgarian.