This paper is to investigate the stress-strain curves for STS 201 austenitic stainless steel over the full strain range. Ramberg-Osgood expression can be used to predict the stress-strain curve up to the 0.2% proof stress. Rasmussen and Shin have developed the approach for stress-strain curve of stainless steels beyond 0.2% proof stress based on the Ramberg-Osgood concept. However, for STS201 stainless steel, two existing concepts were not available for predicting the curves and therefore modified method was discussed in this paper.