Introduction:  Nowadays  the  medical,  therapeutic  and  pharmacological  application  of  magnetic  fields 
(MF)  and  its  biological  effect  has  raised  question  about  the  safety  of  MF.  This  study  aimed  at 
scrutinizing the effect of static MF on the resistance of S. aureus to antibiotic. 
Materials and Methods: This prospective, case–control study was conducted to evaluate the effect of 
low intensity (0.5 mT) static MF on the growth rate and the antibiotic resistance of S. aureus sensitive to 
gentamicin. The studied bacterium is a nosocomial type and the growth rate was calculated by colony 
counting to understand the effect of MF on it. In the next stage, the rate of bacterial growth along with 
the different concentration of antibiotic was studied and the Minimum Inhibitory Concentration (MIC) 
and Minimum Bactericidal Concentration (MBC) were determined. 
Results: It is concluded that the 0.5 mT MF didn't affect the growth rate of S. aureus after 24 and 48 hours. 
The 0.5 mT MF induced a 50 percent decline of MIC and MBC of gentamicin after a 48 hour incubation (MIC 
= 4 6g /cc, MBC = 8 6g /cc in the case group vs. MIC = 8 6g /cc, MBC = 16 6g /cc in the control group). 
Conclusion: Low–intensity MF didn't affect the bacterial growth rate. However, the bactericidal effects 
of gentamicin were greater in the presence of MF. It is possible to apply the static MF for enhancing the 
effect of antibiotic on S. aureus.