A B S T R A C TTextile industries must treat their wastewater before discharge into hydric bodies. This treatment aims at removing the majority of colorants, whose interaction with the environment can cause great damage to nature. The biosorption has often shown an economical and effective technique in removing many of these dyes. Thus is proposed to apply as biosorbent, the Pennisetum purpureum Schumach, 1827 (Poales: Poaceae). (Elephant grass), to treat wastewater containing the dye índigo carmine. The assays of dye removal were conducted in batch mode under the following conditions: varying temperatures (30, 40, 60 and 100 ± 2°C); constant agitation of 150 rpm; pH 5.5; 0.5 g of biosorbent; and different concentrations of dye, 25 to 65 mg.L -1 . The biosorption mechanism was well described by the Langmuir model. The maximum biosorption capacity was 17.51 mg.g -1 of elephant grass dry mass. Thermodynamics investigation indicated that favorable and spontaneous process at temperatures up to 60°C, above that, the system showed a reduction in adsorption capacity. Thus, the use of P. purpureum Schumach, 1827 (Poales: Poaceae) as biosorbent for the removal of indigo carmine dye textile effluents showed as a new effective and economical alternative.