In recent years, medical science has turned to a variety of new products and technologies to halt the spread of infections. The most effective and promising antimicrobial agents being embraced by modern medical science today is silver, which is also one of the oldest. In 1940s breakthroughs in antibiotics such as penicillin, actinomycin and streptomycin, medical science began to shift its attention away from preventative compounds such as antimicrobial silver and focused instead on antibiotic treatments. With increasing drug-resistance and growing concern regarding the over-prescribing of antibiotics, there has been a resurgent interest in the use of antimicrobial silver. Unlike antibiotics, silver appears to be immune to resistance. Thus, the conjugation of antibiotic with AgNP (Silver nanoparticles) would prevent development of resistance by microbes and enhance the antimicrobial property of the antibiotic. This study is based on the synergistic effect of Cephalexin antibiotic with AgNP. The nanoparticles were evaluated for their increased antimicrobial activities with Cephalexin antibiotic against E.coli and S. aureus. The antibacterial activity of Cephalexin was increased in the presence of AgNPs against test strains. The results showed that the combination of antibiotics with AgNPs have better antimicrobial effects.