Fabrication processes in structural components can result in intended or inadvertent material behavior changes due to plastic deformation and residual stresses. In this study, the effect of a residual stress field caused by prior plastic deformation of a beam in four-point bending on the J-R curve of 12.7 mm (0.5 in.) thick specimens of HY-100 steel was investigated. Specimen blanks were deformed in four-point bending to two different levels of deflection prior to machining the starter notch. The resulting residual stress field in a companion test specimen was measured on side surfaces and through-the-thickness by a multiple exposure X-ray diffraction technique. J-testing was performed in three-point bending on undeformed specimens and the two deformed specimen sets using a modified multiple-specimen technique. A decrease in J_Q and tearing modulus, T, with increasing specimen deflection was observed. The decrease in J_Q was comparable to that observed previously in uniformly prestrained specimens.