In this study, an in-situ approach was used to synthesise zinc oxide nanoparticles on the surface of cotton fabric. The effect of alkaline pre- and after-treatment and Zn(2+) concentration was studied on the morphological, structural, thermal, photocatalytic, and antibacterial properties of loaded cotton fabrics. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffractometer, thermogravimetric analysis, and attenuated total reflection Fourier transform infrared spectrometer were used to characterise the properties of loaded cotton fabrics. Alkaline after-treatment of cotton fabric presented more dispersed zinc oxide nanoparticles, and an increase in Zn(2+) concentration led to form agglomerated nanoparticles on the surface of cotton fibres. The loaded cotton fabrics with zinc oxide nanoparticles presented an inhibition zone against Staphylococcus aureus and Escherichia coli. In addition, the stain of methylene blue on the surface of loaded samples was degraded after irradiated under visible light.