Boerhavia diffusa Linn belonging to Nyctaginaceae family is highly reputed plant and has been widely employed in herbal medicine but no work has been carried out on comparison between the antioxidant activities obtained from four different geographical regions. The antioxidant property of methanolic extract of Boerhavia diffusa Linn. was evaluated by estimation of Free radical scavenging activity (DPPH- radical scavenging activity), Total flavonoid contents and free reducing assay method The DPPH radical scavenging activity of B. diffusa was estimated by Inhibitory concentration (IC50) at 517 nm and the free radical scavenging assay was analyzed by Folin - ciocalteu colorimetric method using ascorbic acid as standard, absorbance was reported at 765 nm. Results were reported as DPPH radical scavenging activity (IC50 value) was 350 μg/ml and free scavenging assay was 76.85% (Bangalore) 75.22% (Jhansi),74.88% (pune),73.92% (Delhi) respectively at a concentration of 50 μg/ml. Thus from ongoing study it is concluded that roots of B. diffusa Linn. possess significant Antioxidant activity and can be used for further research study. But the plant which is collected from Bangalore and Pune regions has maximum in vivo antioxidant activity. These shows the geographical conditions affect the phyto constituents of plant.