The pulsed plasma-chemical method was used to obtain zinc oxide-contthe morphology and histograms of the particle aining silicon and titanium oxide nanocomposites (ZnOx-SiO2 and ZnOx-TiO2). To realize the method, a TEA-500 pulsed electron accelerator (Tomsk, Russia) was used. Zinc oxide (ZnO) nanopowder was obtained using the electrospark method. The morphology and phase composition of the synthesized nanopowders were determined using transmission electron microscopy (TEM) and X-ray diffraction (XRD) methods. The cytotoxicity of ZnO, ZnOx-SiO2, and ZnOx-TiO2 nanomaterials on HepG2 and 3T3-L1 adhesive cell lines was studied using thiazolyl blue tetrazolium bromide (MTT; Sigma). It was found that the size of the synthesized particles was in the range of 40-150 nm. The phase composition of ZnO, ZnOx-SiO2, and ZnOx-TiO2 nanomaterials was presented by several crystal structures. The dominant crystal lattice was ZnO with a hexagonal lattice for the ZnO sample, Zn (hexagonal lattice) for the ZnOx-SiO2 sample, and anatase for the ZnOx-TiO2 sample. The morphology of the ZnO, ZnOx-SiO2, and ZnOx-TiO2 nanoparticles was diverse. The cytotoxicity of ZnOx-SiO2 composite nanomaterials was much lower than that of the ZnO nanoparticles. The effect of increasing the viability of cells under the influence of low doses of ZnOx-TiO2 composite nanomaterials was revealed. These research results may present useful information for specialists involved in the development and application of functional nanocomposites.