This study showed the effectiveness of the co-digestion of industrial sludge and food waste under thermophilic conditions. The amount of sludge used influenced the duration at which the optimum percentage of methane is produced. This result is attributed to the microorganisms in the sludge; these microorganisms are required for anaerobic digestion. At high concentrations of sludge in the mixture, the anaerobic digestion process more rapidly achieved the optimum percentage of methane production.