Textile effluents, in addition to high COD, display several problems mainly due to toxicity and recalcitrance of dyestuffs. Innovative technologies effective in removing dyes from large volumes of effluents at low cost and in a timely fashion are needed. Fungi are among the most promising organisms for dye biosorption. In this study dye decolourisation, COD and toxicity decrease of three wastewater models after the treatment with inactivated biomasses of three Mucorales fungi cultured on two different media were evaluated. Fungal biomasses displayed good sorption capabilities giving rise to decolourisation percentages up to 94% and decrease in COD up to 58%. The Lemna minor toxicity test showed a significant reduction of toxicity after biosorption treatments, indicating that decolourisation corresponds to an actual detoxification of the treated wastewaters.