A culture of anaerobic sludge was bioaugmented with Desulfovibrio desulfuricans for the color removal of authentic textile wastewater containing a substantial amount of sulfate, in order to improve the decolorization process. The sulfide produced by sulfate respiration of D. desulfuricans can chemically reduce azo bonds to produce a colorless metabolite in the form of aromatic amines. In the case where the culture of anaerobic sludge was bioaugmented with D. desulfuricans, the decolorization of C.I. Reactive Black 5 showed an increase of more than 14% after 48 h in comparison with that in the culture of anaerobic sludge alone. In the decolorization of authentic textile wastewater, the color removal (about 69.0%) was improved by the mixed culture of anaerobic sludge and D. desulfuricans, compared with results obtained with only anaerobic sludge as reported in our previous work, suggesting that bioaugmentation by D. desulfuricans can be useful for the decolorization of wastewater that contains complex dye compounds and sulfate.