A mangrove medicinal plant Cynometra ramiflora (Family: Leguminosae) was selected to investigate the bioactivities namely antioxidant, antimicrobial and preliminary cytotoxic activity using methanol and chloroform extracts of the leaves and stems, respectively. In 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, 50% inhibitory concentration (IC50) of the methanolic stem extract was found to be 31.62 µg.mL-1. Reducing power of the same extract demonstrated consistent increase in a concentration-dependent manner and was comparable with quercetin while ferric reducing antioxidant power (FRAP) assay revealed potential total antioxidant capacity (84.0 mM Fe (II)/g of extract). In addition, the presence of total phenolics (96.2 mg GAE/g of extract), total flavonoids (166.4 mg QE/g of extract) and tannins content (80.4 mg GAE/g of extract) were determined in the methanolic stem extract. The chloroformic stem extract exhibited moderate antimicrobial activity against a number of bacterial strains while the MIC values of extracts were in the range from 62.5 to 500µg.mL-1. The methanolic stem and leaf extracts demonstrated strong lethality in preliminary cytotoxicity assay using brine shrimp nauplii where the 50% lethal concentration (LC50) values were 1.596 and 4.613 µg.mL-1 respectively. It can be therefore concluded that the methanolic extracts of C. ramiflora possess potential antioxidant, antimicrobial and strong preliminary cytotoxic activity and could be further exploited for prospective scientific exploration towards bioactive principles.