The present investigation highlights the free radical scavenging activity of Melochia corchorifolia, Sida acuta and Saccharum officinarum leaf extracts and their Phenolic contents by determining DPPH, Nitric oxide, Hydroxyl and Hydrogen peroxide scavenging activity. The shade dried leaves were coarsely powdered and subjected to fractional extraction by using chloroform and ethanol. The extracts were subjected to in-vitro antioxidant activity by various antioxidant assays. The antioxidant activities were compared with that of standard Gallic acid from the results obtained, it was suggested that the Phenolic contents of these leaves exhibit strong free radical scavenging activity in all the tested methods and shows maximum scavenging of DPPH, Nitric oxide, hydroxyl and hydrogen peroxide at 100µg/ml concentration compared to chloroform and ethanol extract of leaves. The phytochemical screening of Melochia corchorifolia, Sida acuta and Saccharum officinarum leaf extracts constitutes flavonoids and tannins and the antioxidant activities may be due to the presence of these phenolic compounds