The tensile strength and failure of multilayered stitched carbon/epoxy multiwall carbon nanotube prepreg composites were investigated. Stitching, nano and, both stitching and nano slightly decreased the tensile strength and modulus of stitched and stitched/nano composites. The degradation of tensile properties in using para-aramid stitching yarn was slightly significant compared to polyacrylonitrile carbon stitching yarn due to stitching fiber properties. Prepreg woven pattern did not influence the tensile properties of all stitched and stitched/nano composites. Moreover, the influence of multiwall carbon nanotube on the base/nano and stitched/nano structures was partly inconsistent. Tensile load in stitched/nano composites made severe matrix and warp and filling directional multiple fiber breakages. Nevertheless, delamination areas were arrested by stitching fibers. Brittle tensile breakages and filament pull-out in the stitched and stitched/nano composites were identified.