Raw mixed-dye wastewater from a textile dye-producing plant was partly decolorized by the agaric white-rot fungus, Clitocybula dusenii. The fungus had higher Mn peroxidase (MnP) and laccase activities when grown with dye effluent than in control cultures. The activity of MnP increased commensurately with the proportion of the raw dye wastewater in the medium (control: 20 U l(-1); 10% v/v effluent: 67 U l(-1); 25% v/v effluent: 130 U l(-1); and 33% v/v effluent: 180 U l(-1)). Maximal decolorization rates were achieved over 20 d at 28 degreesC using four-fold diluted dye-containing effluent on a 5 d pre-grown mycelium.