In this study, thermochemical hydrolysis of the waste activated sludge collected from the biological treatment plant of a food industry has been investigated. Thermochemical hydrolysis was used as a pretreatment method to reduce the production of waste activated sludge. In the tests, the effects of pH, temperature and reaction time on thermochemical hydrolysis of waste treatment sludge have been examined. It is observed that hydrolysis increases with the increasing temperature and hydrolysis time at extreme pH values. The nitrogen content in sludge dissolves in parallel with COD. The COD solubility in biomass has reached 18-85%. Furthermore, hydrolysis kinetics of sludge is developed at constant temperature and pH. The results are fitted to first order reaction kinetics.