Attention has long been drawn to the structural features of the Ossetian Nart epic. The tales of the Ossetian epic were formed according to the principle of life cycle presentation. Cycles of tales grouped around heroes were singled out, but the factors of formation of such a structure were not considered. The article examines one of the cycles of the Ossetian Nart epic – the Batraz cycle, which presents a high degree of interconnection of motifs, episodes and plots; parallels with the main versions of the Nart epic are drawn. Batraz is one of the central heroes of the Ossetian epic, whose epic biography is presented quite fully: the tales present the classical life cycle of the epic hero from birth to death. The fullness of the cycle, i.e. its saturation with motifs and plots, contributes to a fuller disclosure of the hero’s character and a wider coverage of his epic life. It is also noteworthy that the stories about Batraz absorb the plots of his father’s biography and can even be transmitted as a single text, which speaks of the formation of the epic structure. The author turns to the motifs and blocks of motifs that make up the cycle and form the fabric of the epic narrative, examines the processes of plot formation, factors that shape the structure of the epic text in the process of oral life, among which the dominant character is first of all emphasized, as well as the process of contamination as a phenomenon that allows the formation and development of the epic text and even the structure of cyclic character. The cycle is characterized by plot-forming motifs characteristic of the Batraz cycle, constant in it, thanks to which the tales receive original development, as well as motifs characteristic of the tales of the epic as a whole, which are plot-forming in the structure of the text.