The paper deals with an unsteady mixed convective MHD flow of a viscous incompressible electrically conducting fluid past an accelerated infinite vertical porous flat plate with suction in presence of radiation and heat generation/absorption. The governing boundary layer equations have been transformed into a two-point boundary value problem in similarity variables and the resultant problem is solved numerically by a fourth order Runge-Kutta method along with shooting technique. The effects of various governing parameters on the velocity field, temperature field, concentration field, skin friction, Nusselt number and Sherwood number are computed and discussed in detailed.