A study is performed to analyze the radiation effects on MHD unsteady natural free convection flow past an inclined surface with variable surface temperature in the presence of transversal uniform magnetic field. The governing equations are transformed into a linear algebraic system and the solution is obtained by employing implicit finite-difference scheme of Crank-Nicolson type. A parametric study is performed to illustrate the influence of radiation parameter, magnetic parameter, Prandtl number and Schmidt number on velocity profile, temperature profile and concentration profiles. The numerical results reveal that the radiation has significant influences on the velocity and temperature profiles. The profiles of the dimensionless velocity, temperature and concentration distributions are shown graphically for various values of the parameters entering into the problem.