AbstractIn this work, bismuth ferrites (BFO) nanoparticles were produced in the form of using sol‐gel technique, followed by annealing in a tube furnace in temperatures from 400 °C to 650 °C. X‐ray diffraction (XRD) results showed the formation of small sizes nanoparticles (NPs) with high purity. Structural analysis displayed that annealing at 600 °C could make BFO NPs be fitted to rhombohedral space group (R3c), with small quantity of spurious phases. The sizes of the BFO nanoparticles determined by transmission electron microscopy (HRTEM) are between 50 to 100 nm. To evaluate the efficiency of BFO in antimicrobial susceptibility tests, the nanoparticles were dispersed through cand tested agar diffusion method and dilution in a 96 well plate using a Gram‐positive strains (Staphylococcus aureus) and Gram negative strain (Escherichia coli). The antibacterial activity of the BFO NPs was tested at concentrations of 2 mg/mL with MIC greater than 60 μg/mL for both bacteria.