In our study we were investigated the in vitro effects of therapeutic concentrations of vancomycin (40 mu g/ml), daptomycin (60 mu g/ml), linezolid (19 mu g/ml), levofloxacin (7 mu g/ml), fusidic acid (36 mu g/ml) and meropenem (24 mu g/ml) on the malondialdehyde (MDA ) levels and polymorphonuclear leukocyte (PMN) functions (phagocytic and intracellular killing activity) in hemodialysis patients. PMNs were isolated from venous blood by ficoll-hypaque gradient centrifugation method. Phagocytic activity and intracellular killing activity were assayed by modified Alexander"s method. MDA level was detected by Beuge method which is as an indicator of lipid peroxidation. All results was evaluated by statisticaly. Vancomycin, daptomycin, linezolid, levofloxacin, fusidic acid and meropenem at therapeutic concentrations did not affect both PMN functions of HD patients before and after HD (p>0.05). It was observed that vancomycin, levofloxacin, fusidic acid and meropenem at therapeutic concentrations increased PMN"s MDA levels of HD patients before HD but decreased MDA levels after HD (p<0.05). Daptomycin and linezolid did not change PMN"s MDA levels of HD patients before and after HD (p>0.05).