Restoration of thermal images distorted by the atmosphere is presented. The method is based on atmospheric MTF analysis, both theoretical and experimental. Thermal IR atmospheric MTF measurements performed simultaneously in both atmospheric IR windows (3- to 5- and 8- to 12-micrometers wavelengths) are also presented. The MTFs were evaluated via point spread function measurements, under various meteorological conditions and different SNRs. Results are analyzed and shown to be in very good agreement with theoretical predictions.