The selective oxidation of ethene over a silver on a-alumina catalyst was studied in a pilot plant with a wall-cooled tubular packed bed reactor. Gas and solid temperatures in the catalyst bed were measured at different axial and radial positions as well as concentrations at different axial position. Total pressure, inlet mole fraction ethene, mass flow rate and wall temperature were varied. The experiments are compared with model calculations. A pseudo-homogeneous model and a heterogeneous two-dimensional model were used for the calculations. Kinetics and heat transport parameters in the model have been determined independently in separate studies. The work is distinctive in the accuracy paid to a large number of experimental details. The models correspond reasonably well with the experiments at all operating conditions. The main problem in the description of the reactor is the inability of the kinetic expressions to predict the reaction rates over the entire range of partial pressures. As a result some systematic deviations are found, in particular in the predicted temperature profiles. The heterogeneous model gives better agreement with the experiments although systematically larger temperature differences are calculated on the basis of available correlations in literature than has been measured. On the basis of this work it is difficult to determine directly whether an influence of chemical reaction is present on the values of the heat transport parameters.