Abstract: Plant mediated synthesis of metallic nanoparticles is an increasing commercial demand due to the wide applicability in various areas such as electronics, catalysis, chemistry, energy, cosmetics and medicine. In the present investigation, synthesis of silver nanoparticles by using leaf extracts of Citrullus colocynthis (L.) Schrader and characterized by using UV spec, FT-IR and AFM. The extract incubated with AgNO3 showed gradual change in the colour of the extract from greenish to reddish brown with intensity increasing during the period of incubation. Hence the leaf extract act as a reducing and capping agent. Nanoparticles were characterized by using UV visible absorption spectra, FT-IR and AFM. The synthesized silver nanoparticles were generally found to be spherical in shape and 31 nm by AFM. FT-IR peaks were in the extract ranging from 1000-4000 cm-1 which confirmed the presence of polyphenols with aromatic ring and bound amide region required for the synthesis and stabilization of sliver nanoparticles.