Wastepaper constitutes approximately half of municipal solid waste, making it a potential source of bioenergy. Newspaper was pretreated with an ammonia-hydrogen peroxide (H2O2) mixture in a shaking bath from room temperature to 80degreesC, and then its enzymatic digestibility was measured. A significant amount of ink was removed from the newspaper slurry by the reciprocating movement of the shaking bath. In addition, the ammonia-H2O2 significantly swelled the substrate, thereby greatly increasing its susceptibility to enzymatic digestion. After pretreating the newspaper with conditions of 40degreesC, 3 h, 130 strokes/min, and 4 wt% ammonia-2 wt% H2O2, the enzymatic digestibility was almost 90% of theoretical, or about 25% higher than that of untreated substrate. Digestibility was also investigated as a function of ammonia concentration, H2O2 concentration, shaking speed, pretreatment temperature, and time.