With an adequate correction, thermocouples can be used for the measurement of high gas temperatures within enclosing walls of different temperatures. Considering heat radiation between thermocouple and surroundings, Fischer developed a two-sensor method for the case with only one unique surrounding surface temperature, which is widely used for this kind of correction. The modified two-sensor method derived in this paper is applicable to the case with different surface temperatures of the surroundings, if inter-reflections between the surrounding surfaces may be neglected. Fischer＇s correction may thus be considered as a special case of this modified two-sensor method. In the case of an infrared radiation burner for example, results of the calculations concerning the temperature profile near to a burner plate show that both correction methods give obviously higher temperatures than those measured. Under the measurement conditions, Fischer＇s correction gives a slightly lower gas temperature profile than the real one corrected according to the authors＇ modified method. A greater difference between these two correction methods may be expected in case of a bigger participation of the sensor surface which faces the burner plate and/or at a greater difference in surface temperatures of the surroundings.