Epoxy paint was homogeneously incorporated with Al2O3(α), Fe2O3(α), SiO2, and ZnO nanoparticles at 1, 2, and 3 wt% with respect to total weight of hardener and undried epoxy, and coated on carbon steel coupons. Corrosion protection performance of the samples was evaluated by linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) in 3 wt% NaCl solution. Analysis of LSV data and thorough analysis of EIS data showed the beneficial effect of all types of nanoparticles at 1 wt%. For 2 and 3 wt% samples, performance was different, depending on the nanoparticle type. However, the sample containing 3 wt% Al2O3(α) showed the best performance among all the tested samples. The results were correlated to the ability of the nanoparticles to block corroding coatings by decreasing the porosity of the dried epoxy paint.