This paper reports the development of inorganic nanoparticles based novel antibiotic. Inorganic nanoparticles have the potential of being used as bactericidal agent due to their effective antimicrobial activity, colloidal aqueous stability and comparatively low toxic profile. Among them, iron oxide and copper oxide were chosen for this study because of the nascent bactericidal properties of both iron and copper. In this work, along with the pure samples of iron oxide and copper oxide nanoparticles, hybrid magnetic nanocomposites of iron oxide and copper oxide with varying molar concentrations of copper precursor were produced by wet-chemical approach. Structural, physical and chemical properties of the prepared samples were investigated using spectroscopic and microscopic techniques like XRD, SEM, TEM, EDAX, Raman, VSM and TGA-DTA. The antibacterial activity of the samples were established against pathogenic strains of bacteria E. coli, B. subtilis, S. aureus and S. typhi by using two different methods. The prepared nanomaterials were very adequate to combat the bacterial growth and their bactericidal efficiency was comparable to the commercial antibiotic gentamycin. Thus these non-toxic hybrid nanocomposites can be used as the potential antibiotic to counter the diseases caused by normal and multi drug resistant pathogenic bacterial strains.