Silver nanoparticles (AgNPs) were evaluated for its possible controlling postharvest pathogen.  Ten endophytic fungi isolated from medicinal plant (Calotropis procera (Ait.) R. Br.), out of these isolates only one canbiosynthesizes silver nanoparticles. The isolate was identified as Fusarium chlamydosporum F25 according to sequence similarities and phylogenetic analysis. The Silver nanoparticles were characterized by Transmission Electron Microscope (TEM), Scanning Electron Microscopy (SEM) and Energy Dispersive Analysis of X-ray (EDX). Four postharvest pathogenic fungi were isolated and identified according to morphological, and microscopical characteristics, the isolated fungi were identified as Alternaria alternata, Fusarium oxysporum, Aspergillus niger, and Penicillium digitatum. The antifungal activity of silver nanoparticles was tested against the isolated pathogens. In vitro silver nanoparticles had a significant effect on growth of all pathogens. Furthermore, silver nanoparticles used to control the postharvest green mould disease of orange caused by Penicillium digitatum. Commercial fungicide Revus top used as a positive control. Silver nanoparticles showed high efficiency against the disease. This study provides the possibility of the use of silver nanoparticles as a protectant fungicide against postharvest disease.