AB ST R AC T This paper presents a new approach to calculate the elastic lateral-torsional buckling moment of I-beams with sinusoidally corrugated webs. The appropriate hand calculation methods to determine the elastic critical moment of corrugated web beams have so far been based on the modification of the warping constant of the cross-section. Instead of modifying the warping constant, the corrugated web is modelled as a thin, equivalent orthotropic plate with uniform thickness. With the usage of the elastic critical moment the inelastic lateral-torsional buckling resistance of sinusoidally corrugated I-beam is determined according to the current Eurocode 1993–1–1:2005.