Visible-light-response Cr/N-codoped SrTiO3 was prepared by a sol-gel hydrothermal method. The comparison studies indicate that Cr-doped and Cr/N-codoped SrTiO3 can be synthesized by this means, but not the N-doped SrTiO3. The theoretical calculations exhibit the defect formation energy of the Cr/N codoping into SrTiO3 is much smaller than that of the N doping into SrTiO3, illuminating that the incorporation of Cr can promote the N doping into the O sites in the SrTiO3. Compared to the Cr-doped SrTiO3, the Cr/N-codoped SrTiO3 photocatalyst shows the high photocatalytic activities for hydrogen production with the quantum efficiency of 3.1% at 420 nm, due to the smaller band gap and much less vacancy defects. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.