In this contribution a simplified procedure that allows analyzing the thermal behavior of laboratory catalytic packed bed reactors is presented. To this end, it is proposed to solve an energy balance inside the reactor that accounts for the heat released by reactions through a suitable approximating function, thus avoiding the formulation and simultaneous solution of the mass conservation balances. The contribution of the different heat transport mechanisms is discussed under different fluid-dynamic conditions. As a reference case study, the catalytic oxidation of ethanol and ethyl-acetate mixture has been selected. Two reactor configurations are analyzed: the conventional laboratory axial packed bed reactor and a geometrically more complex system consisting in two coaxial tubes, the internal one lodging the catalyst sample and the effluent stream flowing counter-currently inside the external annular conduit. The methodology presented here can be readily implemented for most fixed bed catalytic reactors at laboratory scale. (C) 2012 Elsevier B.V. All rights reserved.