An antibacterial activity of apatite-coated titanium dioxide (TiO2) against four types of bacteria (Staphylococcus aureus, Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), and Micrococcus luteus) was investigated. Its antibacterial performance was observed under black light, visible light, and dark conditions. The number of viable bacteria decreased with irradiation time and became most prominent at 24 hours. Distortion of bacterial cells by the nanoparticles was demonstrated by scanning electron microscopy. Apatite-coated TiO2 was fixed on cotton textiles by dip-coat technique, and the antimicrobial properties of corresponding fabrics were then investigated. The effect of irradiation source on antimicrobial activity of coated cotton fabrics was examined, wherein black-light irradiation demonstrated higher antibacterial activity than either visible-light irradiation or dark conditions. Microbial populations of coated cotton fabrics decreased with increasing irradiation intensity. Coated cotton fabrics have been shown to be nontoxic to human dermal fibroblasts. Our findings suggest that the presence of apatite-coated TiO2 shows antibacterial activity in the presence of black light or visible light, suggesting its potential use in reducing the risk of microorganism transmission for textile applications.