Reaction rate data from gasification of a bituminous coal char in H2O and H(2)0/H-2, gas mixtures have been used to synthesize an overall reaction rate model with contributions of the reaction kinetics, the pore development and the surface deactivation. The initial reaction rates could be described as a function ofpH(2)O, pH(2) and T by a Langmuir-Hinshelwood/Hougen-Watson (LHHW) type rate expression. The development of the reaction rate as a function of the carbon conversion (reactivity profiles) could be described by the Random Pore Model, for gasification in H2O. The effect of H-2 on the profile could be described by a lumped deactivation model which is represented by the exponential equation exp(aX), where a includes contributions of T, pH(2) and pH(2)O. The model was successfully used in predicting temperature programmed reactivity profiles.