A composite of CdS and ZnO was prepared by simple solid state mechanochemical method and it was used for photocatalytic degradation of azure A. The photocatalytic efficiency of CdS-ZnO composite was compared with pure CdS and ZnO. The effect of various parameters such as pH, concentration of dye, amount of semiconductor and light intensity was observed. The optimum conditions obtained for this degradation were: Azure A = 3.00 × 10-5 M, pH = 8.5, amount of composite = 0.10 g and light intensity = 50.0 mWcm-2. It was found that coupled chalcogenide CdS-ZnO shows better photocatalytic activity as compared with pure CdS and ZnO for the degradation of azure A in the presence of visible light.