The WO3 loaded Ag-ZnO (WO3-Ag-ZnO) was successfully synthesized by solvothermal method. The catalyst was characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) images, transmission electron microscope (TEM) images, energy dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), cyclic voltammetry (CV) and BET surface area measurements. The photocatalytic activity of WO3-Ag-ZnO was investigated for the degradation of Acid Black 1 (AB 1) in aqueous solution using UV-A light. WO3-Ag-ZnO is found to be more efficient than Ag-ZnO, WO3-ZnO, Ag-WO3, commercial ZnO, prepared (bare) ZnO, TiO2-P25 and TiO2 (Merck) at pH 9 for the mineralization of AB 1. The effects of operational parameters such as the amount of photocatalyst, dye concentration, initial pH on photo mineralization of AB 1 have been analyzed. The mineralization of AB 1 has been confirmed by COD measurements. The catalyst is found to be reusable. (c) 2012 Elsevier B.V. All rights reserved.