Under certain circumstances, beam-to-column joints can be subjected to the simultaneous action of bending moments and axial forces. Although, the axial force transferred from the beam is usually low, it may, in some situations attain values that significantly reduce the joint flexural capacity. Few experimental tests are available and are usually described by their associated moment-rotation curves. An interesting question is how to incorporate these curves into a structural analysis, for the various required axial force levels. The main aim of the present paper is the development of a consistent and simple approach to determine moment versus rotation curves for any level of axial force using a limited set of experiments including the axial versus bending moment interaction. © 2007 Taylor & Francis Group.