A 3-phase, one dimensional, heat transfer model for the fluid catalytic cracking riser reactor is developed. This model incorporates a new detailed kinetic model based on pseudo components' cracking. The model also includes the effect of local temperature on the reaction rate constants, variation of endothermic heat of cracking all along the riser height, and the heat of adsorption of the coke on the catalyst. Also, the developed model is compared with a 2-phase, one dimensional heat transfer model.The proposed model is capable of predicting the products' yields, phase temperatures, and phase velocities all along the riser height. Model predictions are very close to the data reported in literature.