ZnO-TiO2-carbon nanotubes (CNTs) composites are successfully synthesized using microwave-assisted reaction of ZnO precursor in TiO2 and CNTs suspension using a microwave synthesis system and they are used as photocatalysts for photocatalytic reduction of Cr(VI). The results show that the CNTs addition could enhance the photocatalytic performance of ZnO-TiO2 composites. The ZnO-TiO2 composites achieve a maximum reduction rate of 90% at 240 min under UV light irradiation, much higher than those for the pure ZnO (58%) and the ZnO-TiO2 (69%). The improvement is ascribed to the increased light absorption intensity and range as well as the reduction of electron-hole pair recombination with the introduction of CNTs. (C) 2012 Elsevier B.V. All rights reserved.