An energy requirement model of a combine harvester has been developed by suitably integrating the energy models of the machine components. The model calculates the output with ten model coefficients associating four model variables. The crop throughput, travel speed, peripheral speed of the threshing cylinder and total vertical load borne by the ground wheels are the variables of the combine harvester energy model. The rate of specific diesel consumption is the model output. The values of three model coefficients associated with the major energy consuming processes, viz., threshing, traction, and friction at moving components have been assessed utilising a multiple regression technique. The data used for the determination of the model coefficients as well as for their validation relates to the performance test results of seven commercially available Indian made combine harvesters harvesting major paddy and wheat varieties in India. The models predict the specific diesel consumption of these machines.