Aim of the proposed paper is to investigate hydromagnetic radiative convection flow of a viscous, conducting, incompressible fluid through a porous medium between two semi-infinite parallel plates with periodic cross-flow velocity and periodic temperature, taking into account the internal heat generation/ absorption.The flow is subjected to optically thin transparent medium and the uniform magnetic field is applied normal to the flow. For a small time dependent perturbation of the fluid velocity and temperature, the nonlinear equations are solved by asymptotic approximation. The resulting velocity and temperature fields are shown graphically for different values of the physical parameters. The skin-friction and the rate of heat transfer in terms of Nusselt number, at the plates are derived, discussed numerically and shown graphically.