The sorption of pollutants present in watery solutions is an advantageous alternative in relation to the common treatment of effluents, since it reduces the need for techniques that involve the generation of sludge. In the case of biosorption, the sorbent materials generally are of low cost and can be waste or industrial by-products of natural origin. Therefore, the objective of this work was to evaluate the biosorption of the Yellow Reafix B2R 134% dye using a by-product of the brewing industry (malt bagasse) as biosorbent from the analysis of the influence of contact time, temperature and obtaining of the thermodynamic parameters in batch system. The results pointed a similar behavior for the three working temperatures evaluated. The removal process was considered endothermic (13.3822 kJ mol-1), with increase of the solid/liquid interface disorder during the biosorption (0.0468 kJ mol-1 K-1), spontaneous (-874.15 to -1818,24 kJ mol-1) and with activation energy of 35.64 kJ mol-1, what characterizes a sorption of the physical type. In general, the results show that in front of the thermodynamic aspects the malt bagasse has potential in the treatment of effluents containing reactive yellow dye.