The chapter focuses on dynamical Monte Carlo (MC) methods, which are widely used in physics and engineering, and which were introduced in the previous chapter. They are useful to probe the kinetics of heterogeneously catalyzed reactions. Reactions typically are "rare events" compared to diffusion processes, so that the exclusive use of microscopic molecular dynamics simulations is unfeasible or at least uneconomical. Dynamic MC simulations of reactions in zeolites are still in their infancy. It is important to realize that these methods cannot really be isolated from other computational techniques: in the future, combination with quantum chemical computations of the elementary reaction steps, as well as with a transition-state theory and/or short-time molecular dynamics for diffusion, will increasingly contribute to providing deeper insights into the parameters that determine the selectivity and yield of reactions in zeolites. The continued increase in computational power, and the availability of faster and more robust algorithms is the basis for advances in the practical use of statistical mechanics to simulate diffusion and reaction in zeolites. New analytical-theoretical developments, such as mesoscopic and extended mean-field theories, are of equal importance in reaching progress in this field. © 2004 Elsevier Ltd All rights reserved.