The study was aimed to determine antioxidant activity of methanolic extracts of both leaf and root of 12 nos. of therapeutically used mangrove species of Odisha coast using different antioxidant assays i.e., DPPH, FRAP and ‘Reducing Power’. Significantly higher DPPH radical scavenging effect was observed in leaf extracts of Heritierafomes (IC50=13µg/ml). However, in root extract, the activity was higher in Rhizophoraapiculata (IC50=17µg/ml). As far as total antioxidant content is concerned, Avicennia marina showed highest content i.e94.16±5.36 mg AEAC/g dry wt.in leaf sample and87.33±0 mg AEAC/g dry wt. in root sample. The highest FRAP value (4.75±0.08 mM AAE/g dry wt.)  in leaf samples was found in Cerberamanghas. Whereas, highest FRAP value (5.19±0.40 mM AAE/g dry wt.) in root extract was noted in Cynometrairipa. As regard to reducing power, Kandeliacandel showed highest activity e.g.,3.49±0.08 mg AAE/g dry wt. in leaf extracts among the studied species. In root extract, Aglaiacucullata exhibited highest reducing activity (3.35±0.01 mg AAE/g dry wt.). This study revealed that H. fomes, R. apiculata, A. marina, C. manghas, C. iripaand K. candelwere found to be good sources of natural antioxidants for pharmaceutical utilization.