Abstract: In-vitro antioxidant activity of methanolic extract of Rhinacanthus nasutus leaves was determined by DPPH free radical scavenging assay and Reducing Power assays. Ascorbic acid was used as standard and positive control for both the analysis. All the analysis was made with the use of UV-Visible Spectrophotometer. The methanolic extract of Rhinacanthus nasutus leaves had shown very significant DPPH (1, 1-diphenyl-2-picryl-hydrazyl) radical scavenging activity compared to standard antioxidant. The DPPH radical scavenging activity of the extract was increased with the increasing concentration. In DPPH free radical scavenging assay IC50 value of leaves extract of Rhinacanthus nasutus was found to be 34.4 ìg/mL. The reducing power activity of the leaf extract was moderately exhibited. The results concluded that the extract have a potential source of antioxidants of natural origin.