The determination of the optimal distribution of the catalytic activity profile, which maximizes the catalytic effectiveness and the selectivity, in created unsteady state conditions, is analyzed and treated numerically for the case of a consecutive-parallel reaction scheme. The optimal active element distribution is always a Dirac-? function, i.e., all the catalyst is deposited at a specific distance from the center of the catalytic pellet. The main result is that the location of this optimal position varies with time and that the modulation, of the temperature and the reactants concentrations of the external bulk fluid, leads to a considerable increase of the catalytic effectiveness. On the other hand the selectivity was found to be not affected by the modulation except for higher values of ?2 (?2>0.3).