Residual stresses can be introduced into engineering components during manufacture and also by the forces imposed during operation. In this paper methods of measuring residual stress distributions are considered. Examples are included of the types of residual stress distributions that have been determined. Progress in the preparation of a recommended procedure for making the measurements, under the auspices of VAMAS TWA 20 (Versailles Project on Advanced Materials and Standards, Technical Working Area 20), by neutron diffraction are presented. Procedures, using stress analysis and fracture mechanics concepts, for describing the influence of residual stress on crack growth and fracture are discussed. It is shown how an accurate knowledge of any residual stresses present can enable safe and reliable predictions of component performance to be carried out.