In a cracked element, all stresses must flow around the crack, inducing high stress concentrations at the crack tip that are responsible for crack propagation. As the development and application of fiber reinforced composite materials to different engineering structures are increasing gradually nowadays, composite fiber patching techniques are being considered as alternatives to traditional methods of strengthening and fatigue crack repair in steel structures. An experimental program was conducted to study the stress distribution in a patched element, and the effect of varying patch dimensions and stiffness on that stress distribution. Test results showed that single sided patching decreases crack tip strains significantly in the patched face, and increases them in the unpatched face. Finite element analysis of the test specimens were carried out and compared with the test data. The finite element results showed that the stress intensity factor of cracked steel plates with CFRP patching were reduced significantly. © 2006 Taylor & Francis Group.