Graft copolymerization of acrylamide onto commercial acrylic fibers was carried out using benzoyl peroxide as a free-radical initiator in aqueous medium within the 75-$95^{circ}C$ temperature range. In this study, the effects of initiator and monomer concentration, the amount of fiber, polymerization time, and temperature on the graft yield were investigated. The optimum concentration for initiator was found to be $2.0{ imes}10^{-3}$ mol/l and the optimum temperature of $85^{circ}C$. The activation energy of the reaction was calculated to as 35.81 kJ/mol at the temperature interval of 75-$95^{circ}C$. The structures and morphologies characterization of grafted fibers was investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The thermogravimetric analysis data showed that the thermal stability of the acrylic fibers increased with graft yield. The scanning electron photographs showed that the homogeneous appearance of the fiber surface changed and a shell-like heterogeneous structure occurred at the surface with an increasing degree of grafting. The moisture content, water absorption, dyeability, and antimicrobial activity of grafted acrylic fibers were also reported. The results showed that grafting of polyAAm improved the moisture contain, water absorption, dyeability, and antimicrobial activity of fiber.