Introduction. In recent years, Ukrainian researchers have become increasingly interested in accentology. Nowadays it is the least explored field of Ukrainian linguistics. But there are too many mistakes and misunderstandings connected with how and why in this or that way it is better to pronounce different words. The study of Ukrainian accent is multiple-aspect, but the most popular aspect is diachronic, because it allows to show historical suppositions of Ukrainian prosodic system. Diachronic accentology is explored by L. A. Bulachovskyi, I. I. Ogiienko, V. G. Sklarenko, Z. M. Veselovska, and V. M. Vynnytskyi, etc. O. O. Potebnia was the first in Ukrainian linguistics who investigated the accent. He applied a comparative method to the East Slavic stress system, collected accentual material of East Slavic languages. I. I. Ogiienko is another well-known scientist of the XXth century. Besides books devoted to the history of stress system, he systematized the well-organized Ukrainian stress system. The accent in the contemporary East Slaviс languages are typically characterized as either fixed or free in word-formative and form-building paradigms. Matthew Baerman studied the evolution of fixed stress in Slavic.