Abstract: A generalization of irwin's method and a new algorithm, called lsquoquadratic,rsquo are proposed for the extraction of mixed-mode stress-intensity factors (SIF) in three-dimensional cracked-body problems. These new algorithms are evaluated along with the existing ones of Smith, Sanford-Dally and Theocaris-Gdoutos, and their SIF results compared.It is shown that all these algorithms deliver SIF values in good agreement and that they all can be applied reliably to near-tip photoelastic data.