The relationship between the concentration of silane, the degree of surface coverage and the functionalization of multiwall carbon nanotubes (MWCNTs) upon silanization is experimentally investigated. MWCNT silanization is conducted using a c-methacryloxypropyltrimethoxy silane varying its concentration with respect to the weight of the MWCNTs from 3.5% to 1000% (10·). Physicochemical characterization of the MWCNTs points out that the optimum range of silane concentration required to generate adequate surface coverage on the MWCNTs is between one and two times the weight of the MWCNTs. This optimum range of silane concentration is further confirmed by mechanical testing of silanized MWCNT/vinyl ester polymer composites.