When a beam is bent about its major axis, it may twist and move laterally, before it reaches its elastic/plastic resistance in bending. Although the problem of lateral-torsional buckling of steel beams at room temperature has a well-established solution, the same problem at elevated temperature has not. A numerical investigation of the lateral-torsional buckling of steel I-beams subjected to a temperature variation from room temperature up to 700 v C, with the aim of assessing the effects of the residual stresses in this mechanism of failure, is presented in this paper. To this purpose, a geometrically and materially non-linear finite element program has been used to determine the lateral-torsional resistance of steel I-beams at elevated temperatures, using the material properties of Eurocode 3, Part 1-2. The numerical results have been compared to the results of the simple model presented in Eurocode 3, Part 1-2 (1995) and a new proposal that is being considered for approval.