This article presents the results of research aimed at determining the influence of selected nanofillers of vinyl ester resin on the mechanical properties of the cured resin. The influence of the resin with nanofillers as a matrix on the properties of the unidirectional CFRP composite was also investigated. Graphite, silicon oxide and titanium dioxide nanopowders were used as resin nanofillers. Each of the fillers was considered in two different contents, i.e. 1 wt.% and 2 wt.%. The variants with such nanofillers content were compared with the unfilled reference variant. The uniaxial tensile strength tests of the resin samples were carried out, showing the possibility of increasing the strength by 19.35% for the variant 1 wt.% of silica nanopowder content. For CFRP composites, the possibility of increasing the strength in the three-point bending test by 25.57% due to the use of a matrix reinforced with graphite nanopowder with a content of 1 wt.% was demonstrated. Based on the analysis of fracture surfaces performed using SEM microscopy, it was shown that the fillers used lead to a significant improvement in the adhesion of the matrix to the composite fibers.