The creation of effective, environmentally friendly antimicrobial alternatives is becoming more and more important in light of the development of antibiotic resistance. The objective of the present study was to illustrate the biosynthetic process of copper (II) carbonate nanoparticles, CuCo3 NPs, by using Fusarium oxysporum culture filtrate as an antibacterial activity against multidrug-resistant (MDR) clinical bacterial isolates, Staphylococcus aureus. Fusarium oxysporum isolate was diagnosed by PCR. One hundred and sixty specimens of pathogenic bacteria were collected from different sources (wounds, urine, sputum) then the bacterial isolates were diagnosed as Staphylococcus aureus by conventional morphological examination, biochemical tests, and the Vitek-2 system. Fusarium oxysporum culture filtrate was prepared by a culture of the fungus on Czapek Dox broth media modified by adding cornmeal and incubated for 14 days with shaking at 27±2°C and filtered in the last stages using a Millipore. The biosynthesis of CuCo3 NPs was done by adding 1g of CuCo3 Cu (OH)2 to 10 ml of Fusarium oxysporum culture filtrate. The NPs were diagnosed using modern methods, including UV-VIS, FT-IR, AFM, FE-SEM, and EDX techniques. Multidrug-resistant Staphylococcus aureus was tested on the produced Cu NPs. The results indicated that the prepared CuCo3 NPs inhibited pathogenic bacterial isolates of Staphylococcus aureus at concentration of 500, 250, 125, and 62.5 mg/ml.