Silver nanoparticles were synthesized at four different calcinations temperature viz., 150°C, 200°C, 250°C and 300°C by chemical reduction method. Silver nitrate was taken as precursor and sodium citrate as a reducing agent. The prepared silver nanoparticles were identified by UV-Vis absorption spectroscopy. Structural, morphological and size of the synthesized nanoparticles were characterized by XRD, SEM/EDS and particle analysis showed that the nano silver (Ag) samples are spherical with particle sizes of 0-95 nm by using particles size analyzer. Also we confirmed that the size of the silver nanoparticles was affected by the calcinations temperature. Antimicrobial activity of silver nanoparticles is important to control conventional antimicrobial agents. Bacterial and fungal contamination is a serious problem. This work evaluates the potential of nano silver to remove bacterial and fungal contaminants. The Experiment involved with three different bacteria’s viz., Escherichia coli sp., Pseudomonas sp., and streptococcus sp., in MHA medium and three different fungus viz., Aspergillus sp., Pencilluim sp., Rhizopus sp., in SDA medium. The results show that nano silver has a good potential for removing of the bacterial and fungal contaminants in human.