Ni-doped TiO2 nanoparticles were prepared using hydrothermal method and characterized by means of XRD, TEM, and TGA. The detailed characterization results revealed that the catalyst possessed spherical morphology and excellent crystalline and thermal properties. Photocatalytic capability of Ni-doped TiO2 nanoparticles was estimated by means of ofloxacin degradation under solar light. About 70% degradation of ofloxacin (25 mg/L, natural pH) was obtained with 1 g/L catalyst dose. The microbiological analysis was carried by examining its antibacterial activity against E. coli culture on agar plate. The results indicated a decrease in antibacterial activity of drug solution with increase in irradiation time, which further supported the excellent catalytic behavior of the prepared Ni-doped TiO2.