Silver-conjugated magnetic iron oxide nanoparticles (Ag-MNPs) were successfully synthesized and characterized and its effect on certain bacteria was evaluated. The synthesized nanoparticles were tested against six isolates which include Serratia marcescens, Staphylococcus aureus, Escherichia coli, Enterobacter cloacae, Salmonella enterica and Acinetobacter baumannii. The result showed that antibacterial activity of the synthesized Ag-MNPs was found to be effective against Serratia marcescens and Staphylococcus aureus, while the compound was ineffective against some clinical bacterial isolates. The diameters of the zones of inhibition were found to be 20 mm and 27 mm for Serratia marcescens and Staphylococcus aureus, respectively. The Minimum Inhibitory Concentration (MIC) was 10 mg/ml for both organisms. Also, the Minimum Bactericidal Concentration MBC for the two organisms was found to be 20 mg/ml. Therefore, the synthesized compound has antibacterial activity and could be a reliable compound of choice for treating bacterial infections.