Thermoanalytical technique combined with FTIR equipment was used for comparative estimation of thermal behavior of samples with simultaneous identification of gaseous compounds formed and emitted at thermooxidation of solid fossil fuels (oil shale, semicoke, coal) from different deposits (Estonia, Israel, Jordan, Morocco, Bulgaria, Russia). The experiments were carried out under dynamic heating conditions up to 900 degrees C at heating rates of 5, 10 or 50 K min(-1) in a stream of dry air. In addition to CO2 and H2O as major gases evolved, a number of individual volatile species like CO, SO2, COS, methane, ethane, ethylene, formaldehyde, acetaldehyde, formic acid, methanol, chlorobenzene, etc. were determined. Notable differences in the composition of gaseous compounds evolved as well as differences in the absorbance of individual species in FTIR spectra depending oil the origin of fuel and oil the heating rate used were determined.