Synopsis Results from an experimental investigation on steel-fibre-reinforced concrete beams under combined bending and torsion are presented, the principal variables being depth of beam and torsion to moment ratio. On the basis of the observed skew-bending mechanism of torsional failure, equations are derived for ultimate torque. The test results are then compared with the theoretical predictions. The proposed method gives good predictions of the ultimate torque and interaction behaviour of beams under combined bending and torsion.