Decolourization of textile dye containing effluent is a very difficult and challenging task textile industries have to face. Biological dye decolourization techniques can be effectively used in textile effluent treatments as an environmental friendly solution for the pollution created by coloured effluents. During the current study, Reactive Red EXF dye decolourization potential of isolated bacterial strain, Proteus mirabilis was studied. Dye decolourisation was most effective under static conditions and reached 94% decolourization after 72 hours of incubation. Optimum dye decolourization was observed at pH 7-7.5 range and at 40 oC temperature.