In the present study silver nanoparticles were synthesized using aqueous extract of fresh flowers of Tagetes erecta. The aqueous silver ions when exposed to fresh flower extract were reduced and resulted in green synthesis of silver nanoparticles. The synthesized silver nanoparticles were characterized by UV-visible spectroscopy, determination of zeta potential, FTIR, X-ray diffraction and SEM analysis. The UV spectrum of synthesized silver nanoparticles showed maximum absorbance at 430nm i.e. at a conc. of 1.5 ml of extract/10 ml silver nitrate solution. Different functional groups were identified by FTIR image, which contributed to antimicrobial activity. From SEM analysis crystalline nature of synthesized nanoparticles was evident. XRD peaks indicated the structure of nanoparticles and proved that nanoparticles are crystalline in nature. Zeta potential of synthesized nanoparticles was found to be -31.9mv which showed that the green synthesized nanoparticles are stable. Synergistic antimicrobial activity of selected concentration of the plant extract along with the antibiotics A(Penicillin) B(cefixime) showed more antibacterial activity against the selected gram positive and gram negative bacteria (Staphylococcus aureus, Klebsiella, Pneumonia, Escherichia coli, Bacillus subtilis.).Among different combinations the synergistic effect of penicillin is more with the synthesized silver nanoparticles against Klebsiella pneumoniae showing a zone of inhibition of 4.5 cm. The synergistic effect of cefixime is more with the synthesized silver nanoparticles against Bacillus subtilis showing a zone of inhibition of 3.5 cm.