Circadian rhythms are oscillations that occur in a 24 hour period as a result of an endogenous biochemical oscillator known as the circadian clock. It regulates physiological and behavioral processes in all mammals. Hydrogen peroxide (H2O2) is a reactive oxygen species (ROS) molecule that also acts as a signaling molecule. We wanted to look at the connection between oxidative stress and the involvement of circadian genes to then be able to further investigate the effects of methamphetamine (METH) on the redox states in Drosophila. Disruptions in circadian rhythms are often seen in substance abuse disorders. In order to measure oxidative stress we used fluorescent dihydroethidium (DHE) staining and studied the variations in the levels of H2O2 in the wild type (wt) and circadian mutants ClkJrk, per01, tim01 and cyc01 of Drosophila melanogaster. Furthermore, we wanted to know if there was a difference in levels of H2O2 circulating in the head and body of the fly and whether it was under the influence of the time of day. Our data suggests that H2O2 levels vary between wt and circadian mutants and that in the circadian mutants the concentration of H2O2 varies depending on the time of day, while in wt it does not. More H2O2 is found in the head.