This paper describes welded-connection tests that were performed on rectangular hollow sections (RHS). The thickness of the RHS sections varied from 1.6 to 3.0 mm. Both butt welds and transverse fillet welds were tested where the tension load was perpendicular to the direction of the weld. The test results are compared with existing American, Australian, Canadian, and European design formulas, and proposed design formulas are given. The reliability analysis method is used to calibrate the existing and proposed design formulas.