An effective two-stage method for obtaining polyacrylonitrile fibers with antibacterial properties has been developed. The method consists of the incorporation of carboxylic groups into fibers by PAA grafting polymerization followed by fiber impregnation with gentamycin, neomycin, or penicillin solutions. The modified fibers show effective biocide liberation into water and antibacterial activity towards Grampositive and Gram-negative microorganisms (Staphylococuus aureus, Escherichia coli, and Pseudomonas aeruginosa). The presence of antibiotics combined with the modified fibers though chemical bonds has been proved by IR and H-1-NMR investigations.