In the past two decades, there has been increasing interest in prestressed girders with corrugated steel webs in bridge construction. The objective of a recent study at the University of Calgary is two-fold. The first is to review and refine the theoretical background for the shear strength of corrugated steel webs. The second is to experimentally investigate the shear and flexural behaviour of composite prestressed I-girders made with such webs. The analytical study shows that the geometry of corrugated steel webs can be chosen to provide the highest shear strength for the least volume of steel with negligible sensitivity to small variations in the corrugation angle. Contrary to published data, the existence of an additional post buckling shear strength as high as 82% of the total shear strength was experimentally confirmed. The experimental results confirm that while the shear is supported by the corrugated steel web, flexure is almost entirely supported by the prestressing steel and reinforcing bars in the bottom flange in tension, and the concrete top flange in compression.