The scattering coefficient of highly excited atomic levels formed by recombination from a plasma and energetically broadened by plasma field fluctuations is determined. For this purpose, the population of the levels is calculated from a detailed balance equation which is solved consistently together with the corresponding equation for the free electron spectrum. Numerical results are obtained for parameters appropriate for ionospheric conditions. The solution proves to be in no way related to LTE situations, therewith invalidating usual treatments of the problem, which are not consistently based on a detailed balance approach. The theoretical result for the equilibrium coefficient for resonant scattering of radio waves by Rydberg atoms is consistent with experimental data obtained from the ionosphere. This suggests that the considered mechanism is exclusively responsible for the scattering of radio waves in particular and electromagnetic radiation in general. ¿ American Geophysical Union 1993