A few-group coarse mesh method has been developed for the calculation of power distribution in 2-dimensional geometry of a fast breeder reactor by extending Askew's one-group coarse mesh method. This method employs modified macroscopic cross sections including group-dependent corrections for coarse meshes of one point per hexagonal assembly and can be easily incorporated into conventional diffusion codes. Results obtained in few-group 2-dimensional test cases on a prototype fast breeder reactor indicate that this method is as accurate as fine mesh calculations with six mesh points per assembly and the computing time is about ¼ of that of fine mesh calculations.