By making use of plastically adjusted linear elastic fracture mechanics analysis and plastic limit load solutions, a method is developed for reasonable approximation of Rice's path independent J integral which is applicable for test specimens or other configurations which exhibit considerable plasticity prior to fracture. Employing this, J is expressed as a function of load point displacement. Estimations of the J versus displacement relationships developed compared quite well to those previously established experimentally at Westinghouse Research Laboratories for Ni-Cr-Mo-V and A533B steels. For these comparisons, the test specimen configurations considered were three point bend, center notch, and compact tension test specimen configurations, all of which exhibit significantly different plastic limit load slip line flow fields. Thus, the method developed for approximating J is thought to be widely applicable.