The cold work from the manufacturing process of cold-formed sections causes a significant change in the mechanical behaviour and enhances the strength of the material.This paper presents the results of a study on the accurate prediction of the mechanical properties of both virgin stainless sheet materials and cold-worked materials of cold-formed stainless steel sections.This paper first presents a new stress-strain model for stainless steels,which is capable of accurate predictions over the full ranges of both tensile and compressive strains.The new stress-strain model is defined using the three basic Ramberg-Osgood parameters and is based on a careful interpretation of existing experimental data.In the second part of the paper,a finite element method is then presented for predicting the stress-strain behaviour of cold-worked materials,including corner materials and flat materials,in press-braked stainless steel sections.In this method,the effect of cold working on the stress-strain behaviour of cold-worked materials is account for by means of a numerical simulation of the manufacturing process of the press-braked section,with the resulting residual stresses and equivalent plastic strains specified as the initial state in a subsequent finite element simulation of coupon tests.This method is capable of predicting both tensile and compressive stress-strain behaviour of cold-worked materials.The accuracies of both the new stress-strain model and the finite element method are demonstrated by comparing its predictions with experimental stress-strain curves.The proposed finite element method together with the new stress-strain model can be applied in the future in a development of a direct relationship between the virgin material properties and cold-worked material ones.