Transient energy transfer in the hot and the surrounding cold layers of gray radiating gas during expansion has been studied. The gases have been assumed to be perfect and in local thermodynamic equilibrium. The heating of the gas by a diffuse and a collimated component of radiation flux incident on the boundaries from some external source has been considered and the dependence of the physical and radiative properties of the gas on the temperature has also been accounted for. The governing equations have been transformed toLagrangian coordiantes and then solved simultaneously by a finite difference method. The distributions of temperature, pressure and velocity are presented in hot as well as cold gas layers as a function of time for a variety of parameters and initial conditions of physical interest.