Calculating deflections by using the current method proposed in EN1993-1-4 with the value of the secant modulus leads to an over-estimation of deflections. A new methodology for calculating deflections in stainless steel beams, taken into account the material non-linearity and based on an analytical expression for the moment-curvature relationship for stainless steel cross-sections, is being developed. The new approach that accounts for inelastic deflections in stainless steel beams will be proposed based on parametric studies on stainless steel beams.