A new method of glycidylmethacrylate (GMA) radical copolymerization on the surface of commercial cellulose membranes followed by immobilization of synthetic antibiotics on grafted poly(GMA) chains has been developed. Transport and antimicrobial properties of modified membranes have been studied. It has been shown that decreasing of samples permeability is caused by grafting of GMA, and it depends on initiator concentration, duration of reaction and process temperature. Infrared spectrometry and capillary electrophoresis were used to analyze modified samples. Antibacterial properties of membranes modified by nalidixic acid and levofloxacin were studied against gram-negative bacteria E. coli and gram-positive bacteria S. aureus. Higher antibacterial activity of membranes modified by levofloxacin in comparison to those modified by nalidixic acid was shown. Thus, antibacterial activity of membranes modified by 0,5% solutions of antibiotics was 90% for samples with nalidixic acid and 100% for samples with levofloxacin. All samples showed lower antibacterial activity against gram-negative bacteria. The antibacterial activity remained stable for 36 days of membrane operation