Advancements in computational tools and the wide availability of finite element analysis software packages to the structural engineering profession offer the possibility of a more accurate and performance-based fire design of stainless steel structures relative to the prescriptive structural steel fire design methods currently used in practice. Despite these significant advantages, the existing structural steel fire design standards such as the European structural steel fire design standard EN 1993-1-2 as well as the new European standard on finite element analysis based design of steel structures EN 1993-1-14 do not provide sufficient guidelines on the proper and effective use of finite element analysis in the fire design of steel structures. Considering this, in this paper. a novel fire design approach for stainless steel structures based on Geometrically and Materially Nonlinear Analysis with Imperfections (GMNIA) is put forward. In the proposed approach, the GMNIA of stainless steel structures in fire are carried out using beam finite elements, exploiting their computational efficiency. In view of the lack of ability of beam finite elements to consider the influence of local buckling, predefined strain limits are imposed on stainless steel structural elements at elevated temperatures to consider the influence of local buckling on the behaviour of stainless steel structures in fire. In the proposed approach, the failure is signified by (i) the temperature (time) at which a strain limit is attained in a stainless steel element in fire or (i) the temperature (time) at which the stainless steel structure or a member is no longer able to carry the applied loading. In this paper, the application of the proposed GMNIA with strain limits based fire design approach are illustrated for stainless steel beams. In all the considered cases, the proposed fire design approach is extensively verified against the results from nonlinear shell finite element modelling.