The present investigation was carried out to the study of biosynthesized AgNPs using leafextracts of M. azedarach in S. frugiperda. The UV spectrum of the aqueous medium containing silvernanoparticles showed an absorption peak at around 400 nm. FTIR was performed to identify thefunctional groups related to different chemical compounds. XRD pattern confirmed the formation ofnanocrystals in nature. SEM has been used to investigate the morphology of prepared AgNPs. Thirdinstar larvae were exposed to different concentrations of synthesized AgNPs for 24 hrs. The highestmortality was observed in aqueous extract and synthesized AgNPs against third instars larvae of S.frugiperda of LC50 and LC90 values of 36.83(28.05-57.78), 85.71(55.65-425.73) and 25.44(18.27-33.60), 58.65(41.82-143.87) respectively. The silver nanoparticle was found to larvicidal activity againstS. frugiperda.Key words: M. azedarach, UV, FTIR, XRD, SEM