This work is focused on the study of MHD mixed convection radiative heat and mass transfer flow of a steady, viscous, incompressible, electrically-conducting Newtonian fluid which is an optically thin gray gas over a porous vertical infinite plate in the presence of first order chemical reaction and temperature gradient heat source taking into account the induced magnetic field with a magnetic Prandtl number. The governing equations for this investigation are formulated and solved using perturbation technique. Non-dimensional velocity, temperature, concentration, induced magnetic field and skin-friction are discussed through graphs for different values of parameters entering into the problem. © 2013 Pushpa Publishing House, Allahabad, India.