A quasi three dimensional model is used in order to study the flow and heat transfer in a rotary kiln. The final simulation is done by using “Hot Flow”, “Wall” and “Bed” models. Information exchange between models results to a quasi 3D numerical simulation. In the Hot Flow model important phenomena Such as Combustion, Turbulence, Buoyancy effects and radiation are considered. The governing equations are solved with the assistant of “Fluent” program. By solving 3D energy equations and considering the effect of wall swirling in the kiln, the variation of temperature and also heat flux on the surfaces of the kiln is calculated. Heat flux that is obtained by using Hot Flow and Wall model is imported in the Bed model. After that, by solving a one dimensional energy equation in the bed, the variation of temperature in the length of the kiln and the new interface temperature is calculated. This temperature is used as a new boundary condition for Hot Flow and Wall models. In order to become confident from the results of Hot Flow and Wall models, at first a simple model without considering the bed is simulated and the results are compared with available experimental data. Comparison of the results with experimental data reveals the accuracy of models that are used for rotary kiln simulation. Finally by using Hot flow, wall and bed model the rotary kiln is simulated and the results are verified by comparing with experimental data and other numerical results. Key Words Rotary Kiln, Modeling, Heat Transfer, Combustion, Radiation, Kiln