Free radical induced oxidative stress is involved in the pathogenesis of various diseases and disorders.Antioxidants play an important role against this oxidative stress to protect our body. The present study was carried out to evaluate the in vitro antioxidant properties of methanol extract of Ocimum Sanctum. in vitro free radical models like, DPPH, nitric oxide, superoxide,hydrogen peroxide and lipid peroxide radical models. The Aim of present study was to estimate the in vitro antioxidant activity of ocimum sanctum.by in vitro antioxidant methods. ascorbic acid is used as standard. Result are produce in the form of graphical structure.concentration of extract, standard, maeketed prepration are increses as well as DPPH scavenging activity and hydrogen peroxide scavenging activity also increases. then conclusion:ascorbic acid are stronger as compare to extact and marketed prepration of ocimum sanctum.