The various equations of hydrolysis kinetics included into the generalized simulation model (METHANE) were tested on the anaerobic digestion of cellulose, sludge, and cattle manure. The good agreement between the model simulation results and experimental data was obtained. The Contois equation, taking into account a hydrolytic biomass, and the first-order equation with respect to the particulate substrate only, were shown to be the approximations of two-phase hydrolysis kinetics.