Corrugated web girders (CWG) are an alternative to steel girders with flat webs. They consist of a welded I-section with a thin-walled trapezoidally or sinusoidally corrugated web and flanges made of wide flat steel. In comparison with hot-rolled or welded I-girders with flat webs, CWG offer significant material savings. Assuming the same load-bearing capacity, CWG are lighter than those with flat webs, since unperforated CWG can often be loaded up to their plastic resistance without additional web stiffeners. However, the resistance of CWG is often reduced by web openings, which are usually necessary for installations in buildings. As the reduction is dramatic for unreinforced web openings, reinforced web openings are favorable to increase the efficiency of the structure. This paper examines the shear force resistance of trapezoidally and sinusoidally CWG with reinforced circular web openings. Four beam-like specimens with differently reinforced circular web openings were tested. The experimental results are compared with a Finite Element Analysis and with an analytical model. The comparison identifies how the wall thickness of the web opening reinforcement affects the shear force resistance of perforated CWG. Finally, some practical suggestions for designing such girders are presented.