The field of nanotechnology is being now extensively studied by researchers particularly synthesis of nanoparticles with non-toxic, environmentally benign techniques and using mainly microorganisms including bacteria, fungi and algae. These bio-synthesized nanoparticles are aimed to be used as alternatives to the medical agents; however, their activity depends on their size, morphology, distribution and the source of bio synthesis. In this study silver nanoparticles were synthesized from three types of Cyanobacteria naming Nostoc sp., Scytonema sp. and Phormidium sp. Higher antibacterial activity was obtained with Scytonema Nanoparticles (NP) extracts against MRSA followed by Phormidium sp. compared to other algal NP extracts against Staphylococcus aureus, E. coli and Pseudomonas aeruginosa. Chemical analysis of the studied algal NP extracts revealed higher peaks at 3278 cm-1 and 3262 cm-1 for Phormidium and Nostoc algal species, indicating the presence of NP particles to which the antibacterial activity is being attributed.