In this work, the effects of thermal radiation and heat generation on a free convective flow of an incompressible fluid through a porous medium with a periodic surface temperature and first order chemical reaction is investigated. Rosseland approximation was adopted to describe the radiative heat flux. The heat generation is linearly dependent on the temperature. The dimensionless coupled nonlinear partial differential equations were reduced to ordinary differential equations and solved analytically using asymptotic technique. The effects of various parameters apart from radiation and heat generation terms in the governing equation on velocity, temperature and concentration were analyzed in details and shown graphically, as well as with tables. Velocity increases with increase in the heat generation parameter, and decreased with the radiation parameter, R, as well as the Prandtl number.