A measuring system has been developed and a procedure has been proposed for determining the temperature of gas flows and the concentrations of the products of combustion of organic fuels on the basis of the spectral "radiation-absorption" method. A gas multi-wavelength (1.8-4.8 mum) pyrometer-photometer has been created for measuring the self-radiation of gas flows and transmission of probing radiation from a reference source. The optimization of spectral intervals for temperature measurements of combustion products has been made. The test results of the temperature measurements for a laboratory gas burner are presented.