Baker’s yeast effluent is a major source of pollution with high organic load and dark colour. The aim of this study was to examine the photocatalytic degradation of baker’s yeast effluent. Wastewater used in this study was a real wastewater.  An ultraviolet (UV) lamp with 254nm wavelength was used as a source of UV irradiation, TiO2/ZnO composite was used as a catalyst. The effect of the calcination temperature, calcination time, the catalyst amount on decolorization and removal of chemical oxygen demand (COD) of baker’s yeast effluent were investigated. According to the results, the prepared composite TiO2/ZnO with 4:1 molar ratio, treated at 700°C for 60min gave a better result and the maximum decolorization was 35.89% at a catalyst amount of 0.2g/l. COD removal was 14% without catalyst. By using photocatalysis COD removal at the end of the 60min reaction time was 4.85% and 8.94% with 0.15g/l and 0.1g/l catalyst loading respectively.