Aim - to determine the effect of nanodiamonds and carbon nanowires on the survival and ultrastructure of chicken embryo cells. The experiment was carried out on chicken embryos, incubated from eggs of Hy-Line breed. Control and two experimental groups were formed (total number of embryos - 100). Diamond nanoparticles and carbon nanowires were administered on day 3 of incubation as a suspension of a biocompatible dextran. Ultrastructural analysis and general study of embryos state were carried out. The most expressed pathological effects were observed in the group with the introduction of the CNW, which caused visual impairment of embryogenesis that started from the early incubation periods. As for ND we can claim their prolonged impact on the development of embryos, manifested in the gradual deterioration of the embryos condition with the manifestations of the pathology in the provisory organs and the body of embryos. The results of our study demonstrate that both types of nanostructures can cause sublethal and irreversible morphologic changes. Detection of morphological evidence of the impact of nanomaterials at significant distances from the site of administration of nanoparticles shows highly penetrating ability of nanomaterials. The presence of damages specific for each type of nanoparticles shows affinity to various tissues and cellular structures. It is demonstrated that similar, at first glance, impact of nanomaterials, such as the induction of oxidative stress might be caused by specific structural transformations. So, ND cause vacuolization of mitochondria, and the CNW - deformation of their shape and appearance of dark inclusions in them.