Combined effects of Hall currents and radiation on an unsteady MHD free convective flow past a vertical flat plate with oscillatory plate temperature in a porous medium have been studied. The governing equations are solved analytically in closed form. The results obtained are presented graphically. It is found that the Hall currents accelerate the fluid velocity components whereas the radiation has a tendency to retard the fluid velocity components. Porosity of the medium has a tendency to enhance the fluid velocity components. Hall currents reduce the amplitude of the shear stress at the plate due to the unsteady primary flow whereas they increase the amplitude of the shear stress at the plate due to the unsteady secondary flow. Further, the rate of heat transfer at the plate due to unsteady flow increases with an increase in either radiation parameter or Prandtl number or frequency parameter.