Gasification of coal is important for hydrogen generation and also for the integrated gasification combined cycle power generation. Modeling of the gasification reaction is important for the reactor design and operation. Different models suggested for the gasification of coals and chars have been reviewed. The author and his research group have carried out studies on the steam gasification of coal after organo-refining and steam pyrolysis. Based on the studies of the author and his research group on the steam gasification of coal, preextracted coal residues and their chars, a modified model for the steam gasification of coal, has been suggested. This model is based on the shrinking core model and this incorporates the surface and chemical reactivities of coal along with adsorption equations and residual volatile matter.