Effects of radiative heat transfer on an MHD fully developed mixed convective flow of a viscous incompressible electrically conducting fluid through a vertical channel with asymmetric heating of walls in the presence of a uniform transverse magnetic field has been studied. An exact solution of the governing equations has been obtained in closed form. It is observed that the velocity field is greatly influenced by the radiative heat transfer as well as bouyancy forces. The induced magnetic field decreases near the cool wall and it increases near the hot wall of the channel with an increase in radiation parameter. Further, an increase in radiation parameter leads to a decrease in the fluid temperature in the channel. A limiting consideration of the solutions of the governing equations of the flow are analyzed for Ra <<1.