A simulation of the allothermal steam gasification of coal in fluidized beds is presented. The model is basing on the Monte-Carlo simulation of stochastic movements of coal particles in a fluidized bed and the simultaneous calculation of the particle＇s mass loss due to the gasification reaction. All actual process and gasification data such as reaction rate, degree of conversion, product gas evolution etc. are collected related to the particle＇s location in the fluidized bed. The evaluation of these data allows to obtain overall process parameters e.g. residence times, mass contents of the fluidized bed etc. as well as profiles of certain parameters as there are single product gas concentrations, reaction rate etc. as a function of the bed dimensions. A comparison of the results from simulation and experiment is drawn showing a good agreement of both.