The aim of study was to investigate the ultrastructural organization of apical meristem cells of spring wheat plants inoculated by diazotrophic bacteria of Azospirillum genus. Methods. The research of endophytic associations formation between A. brasilense 102 and spring wheat plants (Triticum aestivum L. (T. Vulgare Vill)) sort Rannia 93 were carried out under sterile conditions. Electron microscopic study of cells apical meristems was performed in the transmission electronic microscope Jeol JSM 1200-EX. For each variant the calculation was made among 50 samples in 5 stem apex. Results. During the electron microscopic study of shoot apical meristematic cells of spring wheat grown on sterile substrate inoculated with bacteria Azospirillum brasilense 102, we have investigated the ultrastructural organization of izodiametric cells of initiative apex zone. Under the influence of inoculation the pool of meristems increased, the nuclear – cytoplasmic ratio decreased, the size of mitochondria and plastids increased, mitochondria number of meristematic cells, cristae in mitochondria increased. In cells of mesophillous plants inoculated by A. brasilense 102 strain, there were revealed an increase in the number and size of plastids, mitochondria and peroxisomes compared with controls, there were indicating higher level of cellular respiration in the plants inoculated by this strain. Given the inoculation system cristae in mitochondria was more developed, which may indicate high energy activity of organelles in the inoculated plants. Conclusions. Increasing the number and size of the plastids, mitochondria, peroxisomes, as compared to control indicates a high level of cellular respiration in plants, inoculated by A. brasilense 102 strain. The best level of development of cristae in mitochondria may be evidence of high energy activity of organelles of inoculated plants.