A simple, reproducible method for grafting different carbon fibers (modified and unmodified, high-modulus, and high-tensile) with methacrylic acid is presented. The grafted carbon fibers were characterized by wetting measurements and electrokinetic studies. Scanning electron microscopy micrographs showed grafted polymer chains on all carbon fiber surfaces. The success of the grafting procedure depends on a suitable modification of the fiber surface. The amount and size of the grafted polymer chains on modified carbon fibers depend on the amount of initiator used. Contact angle measurements indicate an increase of the contact angle versus water and a decrease versus diiodomethane. The surface polarity calculated from the surface tensions obtained from contact angle values decreases for all systems under investigation. Zeta (zeta) potential measurements confirmed these results.