Titanium dioxide (TiO2) nanoparticles possess intriguing properties and have been extensively utilized in medical applications due to their exceptional antimicrobial characteristics. The antimicrobial efficacy can be heightened by altering the structural morphology, size, and optical properties through the introduction of transition metal ions (M: Fe, Co, Ni, Cu, and Zn) with a concentration of x = 0.02 into TiO2, thereby producing Ti1 -xMxO2 powder via the sol-gel method at a sintering temperature ranging from 500 °C to 600 °C. The morphological characteristics of Ti1 - xMxO2 were analyzed using FT-IR, UV-DRS, XRD, TGA, BET, and SEM-EDAX techniques. Substituting M-doped TiO2 at a sintering temperature of 500 °C results in all doping ions yielding the Ti1 -xMxO2 anatase phase. Conversely, at 600 °C, the doping ions M: Cu, Co, Zn exhibit a tendency to substitute the TiO2 structure, destabilizing the anatase phase and leading to the formation of an anatase-rutile dual phase with larger crystal size. At elevated temperatures, ions with larger radii than Ti (0.61), namely Cu (0.73), Co (0.75), and Zn (0.74), tend to be substituted, thereby altering the structure of TiO2. The antimicrobial efficacy, evaluated based on the inhibition zone, demonstrates that Ti1 -xMxO2 effectively inhibits the cellular activity of Salmonella typhimurium (Gram -) and Staphylococcus aureus (Gram +) bacteria compared to TiO2.