Radiant temperature has crucial significance in the evaluation of thermal conditions in a structure heated by high-temperature gas-fired radiant heaters. Its value can be influenced by various factors. The article presents the methods of calculating radiant temperature encountered in the literature and contains an analysis of the relation of radiant temperature and the mounting angle of the radiant heater as well as the relation of its power output and dimensions of the burning surface, based on the authors' research. Formulae are given for calculation of radiant temperature and their correct usage is indicated. An example of distribution of radiant temperature in a hall heated by six gas-fired direct radiant heaters with the power output of 12 kW is presented. Examinations of gas-fired radiant heaters conducted so far provide insufficient information about creating thermal conditions at work stands heated by high temperature radiant heaters located in industrial spaces. Hence, the results presented here are of special importance as they refer to parameters characterizing the thermal comfort of people in large capacity halls. (C) 2011 Elsevier B.V. All rights reserved.