Plants have a large number of bioactive compounds with high antioxidant activity. Studies for the determination of the antioxidant activity of different plant species could contribute to revealing the value of these species as a source of new antioxidant compounds. The aim of the present study were to evaluate in vitro antioxidant activities. The extract was prepared by using pure ethanol solvent for Cinchona officinalis stem bark. The in vitro antioxidant activity of Cinchona officinalis stem bark extract was evaluated by using different methods like nitric oxide scavenging activity, free radical scavenging by DPPH method and scavenging of hydroxyl radical (Deoxyribose Method). Vitamin-E was used as standard. The tested plant extract in different concentration showed promising antioxidant and free radical scavenging activity, Concentration 200 µg showed best antioxidant activity compared to other concentration in nitric oxide activity. In DPPH method Concentration 400µg showed maximum antioxidant activity compared to other concentration. From the obtained results we could suggest that this plant extract can be used for antioxidant activity. Key words: Screening, In vitro antioxidant activity, Nitric oxide, DPPH, Deoxyribose method.