Abstract A survey of engineering literature and some of the recent textbooks in heat transfer indicates a lack of knowledge by the authors that the various radiation constants used are no longer valid. The various radiation constants, as reported in the CGS system of units by Birge (3), have been ignored, as well as the recent work of Dumond and Cohen (13) who have further refined the constants reported by Birge. The one particular constant which seems to vary from reference to reference is the Stefan-Boltzmann constant, σ. Values appear to range from 1723 × 10−12 Btu/hr ft2 deg R4 to 1740 × 10−12. An investigation by the author of the atomic constants presented by Birge, and Dumond and Cohen indicates that this constant should be 1714 × 10−12. A complete discussion concerning the various constants is given in the paper.