This paper presents a full slenderness range DSM approach for the prediction of the cross-sectional resistance of ferritic stainless steel hollow sections subjected to different loading conditions using the same strength curve. The analysis is based on the experimental data gathered from the literature and ultimate strengths generated through parametric studies. The cross-sectional resistances to pure compression, pure bending moment and combined uniaxial bending and compression loading conditions are investigated. The proposed method takes into account the reduction due to local buckling for slender cross-sections and the effect of strain hardening for stocky cross-sections, as well as the partial yielding of cross-sections in bending, leading to an accurate full slenderness range DSM design approach. A new method that directly tackles the cross-sectional behavior through the same strength curve is also presented for combined loading conditions. This approach is based on the actual stress distribution of the cross-section and provides more accurate results than the methods considering the uncoupled problem.