Decolorization of dye wastewater before discharge is pivotal because of its immense color and toxicities. In this study, a granular activated carbon based microbial fuel cell (GACB-MFC) was used without using any expensive materials like Nafion membrane and platinum catalyst for simultaneous decolorization of real dye wastewater and bioelectricity generation. After 48hours of GACB-MFC operation, 73% color was removed at anode and 77% color was removed at cathode. COD removal was 71% at the anode and 76% at the cathode after 48hours. Toxicity measurements showed that cathode effluent was almost nontoxic after 24hours. The anode effluent was threefold less toxic compared to original dye wastewater after 48hours. The GACB-MFC produced a power density of 1.7W/m 3 with an open circuit voltage 0.45V. One of the advantages of the GACB-MFC system is that pH was automatically adjusted from 12.4 to 7.2 and 8.0 at the anode and cathode during 48hours operation.