Aqueous solutions of Copper and Zinc nanoparticles with very good stability has been biosynthesized using Terminalia Arjuna bark extract as the inducer and stabiliser for the formation of nanoparticle. The formation of nanoparticles is confirmed and characterised by UV spectral and FTIR analysis. The SEM images revealed the surface morphology and size of the nanoparticles forms by bioreduction method. The copper nanoparticles are in spherical form with size ranging from 10-26nm whereas zinc nanoparticle had the particle size range between 15-25nm. XRD profile revealed the particle size of the biosynthesised nanoparticle. The antibacterial activity of the biosynthesised nanoparticles varied proportionally to the concentration. Copper nanoparticle exhibited maximum antibacterial efficacy than the zinc nanoparticle against the entire organism tested when compared to the positive control [Streptomycin]. Further, K.pneumoniae showed high resistivity to both the biosynthesised nanoparticle when compared to other tested organism. Both the biosynthesised nanoparticles exhibited antihemolytic activity against hypotonic and heat induced hemolysis of erythrocytes. CuNP exhibited maximum efficacy when compared to ZnNP.