A method and a laboratory facility were developed for the purpose of determining inflammation temperature of hydrogen-oxygen gaseous mixtures (HOGM). We have determined the inflammation temperature of HOGM containing the following impurities: Ar, Xe, H2O and tritium within the range of initial gas pressure from 3 to 13 kPa. The results agree well with the available reference and numerical simulation results. The inflammation temperatures of HOGM in the range of initial gas pressure from 2 to 13 kPa increases from 793 to 873 K. Average inflammation temperatures of hydrogen and deuterium mixtures differ no more than 1.6 %. Introduction of inert gases (argon and xenon) into gaseous mixture up to 45 volume percent does not change inflammation temperature significantly. Water introduction (in the range from 2.4 to 25 volume percent) does not cause gaseous mixture inflammation. The effect of tritium -radiation on temperature of GM inflammation within the range of tritium concentration concerned is insignificant and agrees with the results of numerical modeling obtained earlier.