© 2021, Turkish Chemical Society. All rights reserved.45S5 bioactive glasses (BGs) are special class of glasses that form chemical bonds with surrounding bone tissue, which is due to the dissolution behavior of these glass materials. Furthermore, BG shows an antibacterial effect since the dissolution of BG results with high aqueous pH that affect bacterial viability. In this study, the antibacterial activity of Al2O3 doped bioactive glasses (AGs) was evaluated. AGs were produced via the melt quenching method. Functional groups of glasses were evaluated with Fourier Transform Infrared (FTIR) analysis, and glassy structure was evaluated by X-ray diffraction (XRD). Specific surface area, particle size information, and density of milled BG and AGs were obtained using surface area and porosity instrument, laser scattering particle size distribution analyzer and He pycnometer, respectively. Antibacterial activity of bioactive glasses was investigated on Staphylococcus aureus and Escherichia coli via Standard Colony Count Method at 50 mg/mL concentration and different time points, pH change of the media in the presence of BG and AGs at 50 mg/mL concentration was also measured at identical time points. XRD analysis revealed amorphous structure of BG and AGs. Similar specific surface area, particle size and density values were obtained for BG and produced AGs. Antibacterial test results showed that Al2O3 doped 45S5 bioactive glasses had decreased antibacterial activity compared to 45S5 bioactive glass for both bacteria studied.