The lateral torsional buckling resistance of a beam depends on the support conditions. In structures for buildings, coped beams are often used. A numerical model is developed to investigate the influence of copes on the lateral buckling resistance. The model was verified with laboratory tests. This paper describes the background of the numerical model, the test program and the results of the validation. In a companion paper [Maljaars J, Stark JWB, Steenbergen HMGM, Abspoel R. Lateral–torsional buckling resistance of coped beams. Journal of Constructional Steel Research 2005;61(11):1559–75], the results of a parameter study are presented.