Abstract:- Hylocereus undatus is popularly known as dragon fruit. The present study aimed to evaluate the fruit pulp for free radical scavenging activity of superoxide, hydroxyl, hydrogen peroxide and DPPH radical scavenging activities at different concentrations and the activity was expressed using IC50. The IC50 values of purple extracts were found to be 54.94µg/ml, 63.52 µg/ml, 4.45 µg/ml and 190.25 µg/ml respectively for superoxide, hydroxyl, hydrogen peroxide and DPPH radical scavenging activities. The antioxidant activity might be due to the presence of proteins, steroids, carbohydrates, alkaloids, phenolic compounds, tannins, flavonoid’s and saponins in the pulp of Hylocereus undatus.