The present experiment was carried out to investigate whether 9450 MHz and 2450 MHz microwave exposure (MW) affect to the plasmid DNA of Escherichia coli puc 9 or not. Suspensions of E.coli puc 9 were exposed to microwave radiation at 2450 MHz (55,110,165,220 and 275 W for 30 and 60 second) and 9450 MHz (2.65mW/cm(2) for 10,20,40 and 60 minutes). However, plasmid DNA of E.coli puc 9 were also exposed to 9450 MHz (10,20,40 and 60 minutes) and 2450 MHz (55,110,165,220 and 275 W for 30 and 60 second) Microwave. After exposures of E.coli puc 9, the plasmid DNA were isolated and evaluated by AGE assay. We found that amount of plasmid DNA was not changed in 9450 MHz and 2450 MHz MW exposure. The difference of temperatures between before and after 2450 MHz MW exposures were found to be significant (P<0.01). It was concluded that E.coli puc 9 plasmid DNA was not affected by 9450 MHz and 2450 MHz Microwave radiation.