A mathematical model is developed to examine the sensitivity of the breakthrough and cyclic performance of fixed beds with respect to system parameters. As a process model is integrated a single time, sensitivities are simultaneously calculated. For example, the impact of mass and energy transfer effects, particle sizes, adsorbent layer thicknesses, and feed temperature and pressure can be determined by calculating the derivatives of the outlet concentration, outlet temperature, or a process performance measure with respect to the various parameters. Several examples are considered. To establish a basis, we first consider breakthrough of single beds. The adsorption of hexane on BPL carbon is contrasted with the adsorption of nitrogen on carbon molecular sieve, and joint mass and energy effects are considered by studying the adsorption of nitrogen on BPL carbon. We then consider the periodic performance of adsorption cycles. The sensitivity of a periodic state is investigated by examining a two-bed PSA system. The solution method presented can be adapted for the sensitivity analysis and subsequent optimization of a large number of adsorption systems.