The guanidine-based antimicrobial polymers were grafted onto the surface of beeswax latex particles stabilized with or without amphoteric surfactant, n-dodecyl-N,N-dimethylglycine. N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) was used as a coupling reagent to introduce the covalent bonding or ensure sufficient binding force. The resulting novel beeswax latexes were utilized as a dual-functional paper additive, which improved both water-vapor resistance and antimicrobial activities of the paper. Compared with control sample, the water vapor transmission rate of the paper was reduced significantly. The antimicrobial activity of paper against E. coli was also improved substantially even at a low dosage of the beeswax latex derivatives (20 mg/g fiber).