The study of unsteady magnetohydrodynamic heat and mass transfer in MHD flow past an infinite vertical oscillating plate through porous medium, taking account of the presence of free convection and mass transfer. The energy and chemical species equations are solved in closed form by Laplace-transform technique and then perturbation expansion for the momentum equation. The results are obtained for velocity, temperature, concentration, Sherwood number, Nusselt number and skin-friction. The effects of various material parameters are discussed on flow variables and presented by graphs. A parametric study of all parameters involved was considered, and a representative set of results showing the effect of heat radiation, reaction parameter, Grashof numbers, Hartmann number and permeability factor were illustrated.