The problem of the thermal diffusion and magnetic field effects on combined free-forced convection and mass transfer flow past a vertical porous flat plate, in presence of heat generation is studied numerically. The governing momentum, energy and concentration equations are converted into a system of non-linear ordinary differential equations by means of similarity transformation. The resulting system of coupled non-linear ordinary differential equations is solved numerically by using shooting method. Numerical results were presented for velocity, temperature and concentration profiles within the boundary layer for different parameters of the problem as suction parameter, heat generation parameter, Soret number, Dufour number , magnetic parameter and other . Also the effects of the pertinent parameters on the skin friction, the rate of heat and mass transfer are obtained and discussed numerically and illustrated graphically .