Dried powdered stem of Psidium guajava was successively extracted with acetone, methanol and water respectively and subjected to antioxidant activity. Methanolic and aqueous extracts was used for the evaluation of antioxidant activity. The activity was determined at ambient temperature by means of a 2,2-diphenyl1-1-picrylhydryzyl (DPPH) spectrophotometrically with detection scheme at 520 nm. The activity was evaluated by the decrease in absorbance as the result of DPPH colour change from purple to yellow. The higher the sample concentration used, the stronger was the free radical-scavenging effect. The results obtained showed that methanol extract has almost same antioxidant activity as of ascorbic acid while aqueous extract showed less antioxidant activity. This study revealed that guava stem extracts comprise effective potential source of natural antioxidants which might be helpful in preventing the progress of various oxidative stresses.