The objective of this study is to investigate thermal diffusion and radiation effects on unsteady free convection heat and mass transfer flow of viscous, incompressible and electrically conducting fluid past an infinite vertical flat plate embedded in porous medium in the presence of hall current under the influence of uniform magnetic field applied normal to the flow. A general exact solution of the dimensionless governing partial differential equations is obtained by the usual Laplace transform technique without any restriction. The effect of flow parameters on velocity, temperature, concentration, rate of heat transfer and the rate of mass transfer are studied through graphs. © Research India Publications.