This study reports decolorization of Rhodamine B and Congo red by a partially purified laccase from Lentinus polychrous Lév. in the presence or absence of 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonate) diammonium salt (ABTS) as a redox mediator. The decolorization study showed that about 90% of Rhodamine B could be decolorized within 52 h, whereas Congo red could be decolorized more than 75% within 3 h. The most effective concentration of the redox mediator was 0.10 mM ABTS. The optimum pH for Rhodamine B decolorization was at pH 4.0-5.0 and optimum temperature was at 50 ºC. The optimum pH for Congo red decolorization was at pH 6.0-7.0, but increasing temperature had less of an effect. The results and availability of the fungus indicated that laccase from L. polychrous Lév. has high potential for the treatment of waste dyes.