A novel white rot fungus Pseudolagarobasidium acaciicola AGST3 was investigated for the production of laccase under solid state fermentation. The effects of fourteen medium components were screened by the initial screening method of Plackett-Burman. Each of the components was screened on the basis of a ‘p’ (probability value) that was above 95 % confidence level. Tween 80, CuSO4·5H2O, glucose and FeC6H5O7·NH4OH were identified as significant components for laccase production. Central composite design using response surface methodology with four significant variables was used in this study to optimize significant correlations between the effects of these variables on laccase production. The optimum concentrations of Tween 80, glucose, FeC6H5O7·NH4OH and CuSO4·5H2O were (g/l): 0.6625, 0.437, 0.037 and 0.6625, respectively, for maximum laccase production. Compared to the unoptimized medium, the laccase production (5.35 × 105 U/g of substrate) increased 1.6-fold under optimized condition. Furthermore, the crude laccase obtained was used for the decolorization of structurally different dyes, and 11–96 % of decolorization was obtained after 24 h of incubation.