Decoloration by Trametes versicolor of molasses wastewater from an alcoholic fermentation factory was studied. Tests varying the concentrations of carbon source, nutrients, initial pH and mycelia were carried out in order to analyze their influence on the percentage decolorization, COD removal and decrease of ammonium content of the wastewater. Satisfactory results were obtained working with a low sucrose concentration and adding KH2PO4 as the only nutrient. In this way, 82% color elimination, 77% COD removal and 36% N-NH4+ decrease were attained.