Ultimate state of structural members has been widely used for the purpose of seismic design and rehabilitation in seismic standards. Even, common damage indices such as Park and Ang use ultimate state of structural response, known as ultimate deformation. This deformation can be expressed as displacement or, rotation and, curvature of flexural members. In this study, correlation between ultimate curvature and depth of I and, H shaped structural steel sections has been investigated and, a simple relationship to estimate ultimate curvature is presented. It is shown that, this relationship is accurate enough to replace the time-consuming pushover analysis approach to obtain ultimate curvature of mentioned sections.