The radiative heat transfer between parallel plates separated by an absorbing gas with a “picket-fence” absorption coefficient is treated by a variational technique. For the heat transfer, a simple rational algebraic expression is obtained and the variational results are found in excellent agreement with the numerically “exact” results reported recently by Reith et al.( 8) An expression for the extrapolation distance is also deduced and the results are compared with the values reported earlier by Bond and Siewert.( 5)