The crude alcoholic extracts of various parts of five different Bangladeshi mangrove plants (Amoora cucullata, Caesalpinia bonducella, Cerbera odollam, Derris uliginosa and Sonneratia caseolaris) were screened in-vitro for anti-oxidant activity using the 1,1-diphenyl-2-picryldydrazyl-hydrate (DPPH) free radical scavenging assay. Of all of them, the ethanolic extracts of the leaves of Derris uliginosa and Sonneratia caseolaris showed potential antioxidant activity ($IC_{50}$: 94.406 and 26.30 mg/ml respectively) whereas the ethanolic extracts of aerial parts of Derris uliginosa, barks of Cerbera odollam and leaves and stems of Caesalpinia bonducella showed moderate activity ($IC_{50}$: 125.89, 211.35 and 301.99 mg/ml respectively). Mild anti-oxidant activity was observed with the methanolic extract of leaves of Amoora cucullata and ethanolic extracts of fruits of Cerbera odollam.