This paper deals with the rapid photosensitized biosynthesis of silver nanoparticles using aqueous extract of flowers of Cascuta reflexa. The reaction was carried out in ambient sunlight. The mixing of aqueous solution of silver nitrate and the flower extract shows color transitions from yellow to light brown and finally dark brown colour, indicating the formation of silver nanoparticles. As synthesized the nanoparticles were characterized by various techniques such as UV visible spectroscopy, XRD, FT-IR, TEM. The TEM analysis revealed that the particles were predominantly spherical and size ranging from 20 to 50 nm. The antioxidant properties were tested by FR AP assay method. The antibacterial properties of synthesized Nanoparticles were tested against pathogens such. P.aeruginosa, E.coli, B. subtilus and S.aureus.