The present study was aimed to investigate the total phenols, flavonoids, carotenoids, antioxidant activity and antimicrobial activity of the bark extract of Mallotus tetracoccus(Roxb.) Kurz. Total phenols, flavonoids and carotenoids in the extract were found to be 55.35 ± 0.13 mg GAE, 260.3053 ± 1.413 mg QE and 0.182 ± 0.005 mg/g, respectively. The reducing power and metal chelating activity of the bark extract was said to be increasing with increasing concentration. The metal chelating activity (IC50) of the M. tetracoccus bark extract was found to be 647.4 ± 0.321 µg/ml, which was higher compared to the standard, ethylenediaminetetraacetic acid (EDTA; 1.89 ± 0.03 µg/ml). Antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric thiocyanate (FTC) andthiobarbituric acid (TBA) methods. The antioxidant activity (IC50) of the bark extract was said to be 0.504 ± 0.002 µg/ml by (DPPH) method. The total antioxidant activity of M. tetracoccus ethanolic bark extract was found to be 275.21 ± 0.21 mg equivalent of ascorbic acid/100 g of plant extract as determined by phosphomolybdenum method. The antibacterial studies of the ethanolic bark extract was also tested at different concentration of extracts, where 250 mg/ml concentration of extract showed good inhibitory activity against all the clinically important disease pathogens compared with standard antibiotics like streptomycin and penicillin. The highest inhibition was noted in order of Klebsiella pneumonia (25.33 ± 0.37 mm), Staphylococcus aureus (22.83 ± 0.31 mm), Vibrio cholerae(20.00 ± 0.31 mm) and Escherichia coli (20.22 ± 0.26 mm). Thus, the bark extract of M. tetracoccus was said to possess significant antioxidant and antimicrobial activity, which suggests its use in traditional medicine. Key words: Mallotus tetracoccus, antioxidant, 2,2-diphenyl-1-picrylhydrazyl (DPPH), reducing power, phenols, phosphomolybdenum activity, ferric thiocyanate (FTC),thiobarbituric acid (TBA), biological activity.