Cold-formed stainless steel structural members are widely used due to their high corrosion resistance and high resistance-to-weight ratio. They are usually members with high width-to-thickness and high height-to-thickness ratios; therefore, due to its susceptibility to buckle a strong attention to instability phenomena such as web crippling, where the web locally buckles due to concentrated transverse forces, must be taken. As the existing design standards for stainless steels are adopted from the specifications for carbon steels, framed in the European Project SAFFS (Structural Application of Ferritic Stainless Steel), a new expression to predict the web crippling resistance of stainless steel cold-formed members has been obtained. Within this work the new proposal corresponding partial safety factor, γM, will be determined. The study might include some readjustments of the new expression to make it suitable to be incorporated in the current design rules for stainless steel EN 1993-1-4 (2006).