In this study, the effect of fluoroquinolones on the expression of methicillin resistance in Staphylococcus aureus strains was investigated. Oxacillin and fluoroquinolone susceptibility of the strains was determined using microdilution method recommended by the National Committee for Clinical Laboratory Standards. The study was performed by four heteroresistant S. aureus and S. aureus ATCC 29213 strain, all of which are fluoroquinolone susceptible. Population analysis profiling was performed to determine the oxacillin resistance of the strains after their exposure to 0.5 x MIC of the fluoroquinolones. After the ciprofloxacin and levofloxacin exposure among the heteroresistant strains, it was seen that there was about 100-fold enhancement in their resistance rates compared with the control. Growth curve was obtained by plating onto Tryptic Soy Agar with and without oxacillin, from the incubation of the strains with and without 0.5 x MIC of the fluoroquinolones at various time points (8 h and 20 h). After the exposure to ciprofloxacin, the levels of increase detected in the resistance index of the heteroresistant strains was 1-10 fold at 8 h, and 0.6-100 fold at 20 h. After the exposure to levofloxacin, the levels of increase found in the resistance index of the heteroresistant strains at 8 h were 1-200 fold and at 20 h were 17.5-3000 fold. After the exposure of heterosistant strains to various concentrations of ciprofloxacin, the levels of oxacillin resistance increased in parallel to the increasing concentration of ciprofloxacin and it reached the highest level in 1 µg/mL. The resistance index rises up to 0.01 after the exposure to various levels of levofloxacin. This study showed that various periods and levels of fluoroquinolone exposure seemed to increase the oxacillin resistance in S. aureus strains.