Metal nanoparticle synthesis is an interesting area in nanotechnology due to their remarkable optical, magnetic, electrical, catalytic and biomedical properties, but there needs to develop clean, non-toxic and environmental friendly methods for the synthesis and assembly of nanoparticles. Biological agents in the form of microbes have emerged up as efficient candidates for nanoparticle synthesis due to their extreme versatility to synthesize diverse nanoparticles. In the present study, an eco-favorable method for the biosynthesis of silver nanoparticles using Gracilaria edulis seaweed and evaluation of antibacterial activity against Gram positive bacteria (Staphylococcus aureus, Streptococcus pyogenes, Bacillus subtilis) and Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae). The silver nanoparticles and G. edulis seaweed showed antibacterial activity and proved their efficacy in controlling the pathogenic bacterial strains. AgNPs exhibited strong antibacterial activity compared with seaweed extract. The synthesized silver nanoparticles using seaweed revealed interesting properties that could be potentially used for pharmaceutical applications.