C-N-S tridoped TiO2 nanoparticles were synthesized by sol-gel method using thiourea as a source compound for carbon (C), nitrogen (N) and sulphur (S). The crystalline phase and morphology of the doped and undoped TiO2 nanoparticles are analyzed by XRD and FESEM. FTIR confirms the bonding interaction of C, N and S in TiO2 lattice. Compared to the doped samples undoped sample annealed at 600°C shows more absorbance in the visible region due to the existence of rutile phase. Presence of oxygen vacancy is confirmed from the photoluminescence spectra. XPS indicates the existence of the carbon atom in the form of carbonaceous species on the surface of the TiO2 and absorbs the visible light to enhance the photocatalytic activity. The photocatalytic activity of C-N-S tridoped TiO2 nanoparticles were evaluated for the degradation of Rhodamine B organic dye under the visible light irradiation. Maximum of ~ 100% degradation exhibits for the C-N-S tridoped sample (D4) calcined at 600°C. This highly active photocatalytic performance is associated with the existence of oxygen vacancies, the acidic sites on the surface (SO42-) and the mixed phases of anatase and rutile in TiO2 lattices.