The influence of external mass transfer limitations on optimum temperature operations policies, and on the reaction and deactivation parameters is determined for a first-order primary reaction and first-anddth-order reactant-independent deactivation kinetics occurring in a fixed-bed reactor. This is now done using the correct optimum temperature operations criterion. The rate of temperature rise is lower when external mass transfer limitations are present compared to the diffusion-free condition. The apparent activation energy for reaction is not only different from its intrinsic value but it is also time-variant along the optimum temperature operations policy.