A series of catalytically active CeO2/ZnO nanocomposites with different molar ratio (CeO2: 1, 2, 3, 4, 5 and 6 mol%) were successfully synthesized by hydrothermal method. The synthesized nanocomposites were critically investigated using Powder X-ray diffraction technique, Transmission electron microscopy, Selected area electron diffraction and UV-vis diffused reflectance spectra analysis. Powder X-ray diffraction spectra revealed the presence of diffraction peaks of face-centered cubic phase of CeO2 and hexagonal wurtzite phase of ZnO. Transmission electron microscopic analysis revealed that nano composites consist of ZnO nanorods and CeO2 nanoparticles; where, CeO2 nanoparticles were clinging on the surface of ZnO nanorods. UV vis diffused reflectance spectra analysis revealed the good absorption of all the samples towards UV light. The photocatalytic efficiency of CeO2, ZnO and CeO2/ZnO was compared by using methylene blue dye as probe molecule. CeO2/ZnO nanocomposites were found to possess superior photocatalytic activity as compared to their monocomponent counterparts. Furthermore, CeO2/ZnO with 5 mol% CeO2 presented best photocatalytic performance. Additionally, influence of different process variables on the rate of degradation of methylene blue was investigated using CeO2/ZnO with 5 mol% CeO2 as catalyst. Maximum degradation of methylene blue was observed in alkaline region at a catalyst dosage of 1.00 g/L. (C) 2016 Elsevier B.V. All rights reserved.