Radiation and thermal diffusion effects of magnetohydrodynamic flow for non Newtonian fluid through a porous medium past an infinite porous flat plate arc presented. The flow under consideration obeys Maxwell rheological model. Solutions for velocity, temperature and concentration distributions arc obtained with the help of finite difference method. The effects of various parameters such as relaxation parameter λ of the Maxwell fluid, permeability of the fluid K, magnetic parameter M, Dufour number Df, Soret number Sr, Prandtl number Pr, radiation parameter N and Schmidt number Sc on the velocity, temperature and concentration profiles are studied and illustrated graphically. We obtained also the rate of heat transfer and concentration gradient during the course of discussion.