Strontium titanate nanoparticles were synthesized by a microwave-assisted solvothermal reaction of SrCl2-6H(2)O,Ti(OC3H7)(4) in KOH methanol-oleic acid solution. The products were characterized by TG-DTA, XRD, TEM, BET surface area and XPS. The photocatalytic activity was determined by DeNO(x) ability using LED lamps with various wavelengths such as 627 nm (red), 530 nm (green), 445 nm (blue) and 390 nm (UV). The nanoparticles of perovskite type SrTiO3 with the particle size of 15-18 nm were successfully synthesized. The photocatalytic activity of SrTiO3 under visible light (lambda = 530 nm) irradiation could be generated by modification of the surface with the carboxyl group (-COO) from oleic acid which enabled the absorption of visible light. (C) 2010 Elsevier B.V. All rights reserved.