The kinetics of hydrogenation reactions of acetylene-ethylene mixtures over a Pd/alpha-Al2O3 commercial catalyst was studied. Reaction rates were measured by using a gradientless reactor. The kinetic expressions derived, based upon a mechanism involving two types of active sites produced on the palladium surface by carbonaceous deposits, were used for the interpretation of experimental results. The kinetic parameters in these equations and in recently published kinetic expressions were estimated by using multiresponse technique. Statistical analysis of regression showed that the proposed kinetic model describes the process more adequately than do the competitive models.