The aim of this investigation is to study MHD free convection unsteady flow of an in compressible, electrically conducting, viscous, rotating liquid in a non homogeneous porous medium past an infinite isothermal vertical plate with constant source / Sink in the presence of a uniform magnetic field applied perpendicular to the flow region. Expressions for primary and secondary velocities and temperature distribution, skin-friction coefficient and rate of heat transfer are obtained and discussed numerically.