Rapidly synthesized phyto-mediated silver nanoparticles (Ag NPs) using Artemisia nilagirica aqueous leaf filtrate has been confirmed through UV-visible spectrophotometer. The synthesized Ag NPs were further characterized using Fourier transform infra-red (FTIR), X-ray diffraction analysis (XRD) to determine the present of functional groups and average particle size (6.723 nm with cubic nature), respectively. Spherical shape (30 nm) of Ag NPs was confirmed by scanning electron microscopy (SEM). Bioefficacy of these nanoparticles showed larvicidal and pupicidal properties than the aqueous leaf extract treatment alone against developmental stages (I-IV instars and pupa) of malaria vector Anopheles stephensi and dengue vector Aedes aegypti at 0.25% concentration level. The LC 50 (LCL:UCL at 95% confidence limit) values of I-IV instar and pupa of An. stephensi were recorded at 0.