Biological decolorization of Synazol Blue and Synazol Red were comparatively studied using three different wild-type white-rot fungi strains (Pleurotus ostreatus, P. sajor-caju and Ganoderma lucidum) isolated from nature. The initial dye concentrations in the medium were 250, 500 and 1000 mg/L, respectively. All the organisms studied decolorized Synazol Blue to varying degrees. At low dye concentration, fungi strains resulted in the best decolorization, but mycelia negatively affected from increasing dye concentrations.