A numerical study on a combined radiation and forced convection heat transfer of superheated steam, which is a radiation participating real gas, in thermally developing laminar flow through a parallel-plate channel has been conducted to investigate charactcristics of superheated steam drying. The integrodifferential energy equation was solved using an implicit finite-deference technique with a marching solution procedure and an exponential wide-band model for the treatment of the radiative transfer part. Comparison of results with and without gas radiation in various conditions shows that a fluid radiation decreases the temperature of main stream, but increases the total heat flux at a heat transfer surface. Furthermore, the results show that the fluid radiation decreases the inversion point temperature approximately to 150∼240°C with the increase of optical thickness. This numerical result agrees in the order of magnitude with the previous experimental studies, but is lower about 100K than that of former theoretical predictions without considering fluid radiation.