Résumé : Accurate temperature measurements in reactive combustion systems are crucial for kinetic and heat transfer studies. Intrusive temperature measurement methods, such as thermocouples, are still widely used in experimental combustion research applications. Thin wire customized type B thermocouples, (Pt Rh6%-Pt Rh30%), coated with BeO (Beryllium oxide) - Y 2 O 3 (Yttrium oxide) anti-catalytic ceramic, are used in this study to measure the flame temperature at low pressure of three H 2 /CH 4 /CO-air flat flames at different equivalence ratios. In the range 50 0–170 0 K, the measured flame temperatures are corrected for radiation losses with two different well-known approaches, the experimental electrical compensation method (ECM) and the numerical heat transfer correction method (HTM). Both methods are applied to the measured flame temperatures, and their performance and limits are assessed, highlighting the primary sources of uncertainties. This work aims to shed light on the crucial issues related to the temperature correction methods primarily used in the experimental combustion diagnostic. A strategy to reduce the uncertainties of the two methods is proposed and applied to the measured temperature flames. The propagation of the errors on the main parameters involved in the numerical correction method is carried out to estimate the final uncertainty of the corrected gas temperatures. Finally, a new approach is proposed to quantify the error incurred by neglecting conductive heat transfer between the thermocouple bead and the connecting thermocouple wires.