In this work, Azadirachta indica leaf extract and the ultrasonic method were applied for the fabrication of a CuO/Ag-based nanocomposite. The CuO/Ag was characterised using different analytical methods such as FTIR, SEM, EDX, and XRD. The well diffusion method was used to evaluate the antibacterial activity of non-calcined and calcined CuO/Ag against some hazardous bacterial strains. After the incubation period, remarkable zones of inhibition were observed around the loaded CuO/Ag. The maximum zones of inhibition were found to be 17.9 (± 0.39), 20 (± 0.17), and 14.3 (± 0.31) mm for E. coli, S. aureus, and S. enterica, respectively. Experimental findings indicated that non-calcined CuO/Ag was a more effective antibacterial agent as compared to calcined CuO/Ag.