This study investigates the effect of hydrogen peroxide (H2O2) dose, pH and reaction time on the disintegration of Waste Activated Sludge (WAS) by H2O2oxidation alone and H2O2 oxidation with acid/alkaline hydrolysis.H2O2 oxidation with alkaline hydrolysis enhanced the sludge disintegration and dewaterability. Under the optimum operating conditions (pH 11, 1250 gH2O2/ kg TS and reaction time 45 min), H2O2 oxidation aided with alkaline hydrolysis resulted in good removal of solids (TS 28.1, VS 25.3, MLSS 24.6 and MLVSS 21.4), CST reduction 28.4 and sCOD concentration 8863 mg/L. The current method was shown to be an adequate pretreatment for further treatment of the waste activated sludge by biological digestion. © 2016 Taylor & Francis Group, London.