A numerical method for determination of stresses in two-dimensional elastic bodies with high stress concentrations is presented. Major emphasis is placed on bodies with a notch having a fillet of small radius and bodies with a crack of small width. These static boundary value problems are formulated in terms of boundary integral equations of a type used previously by Barone and Robinson for sharp notches and cracks. For the fillet problem a small inner region containing the fillet and bounded by a circle is separated out and analyzed numerically under the loading system of each of the Williams' solution of the corresponding sharp notch. The results are then used to develop analytical solutions for the intermediate region adjacent to the fillet region. In this way the details of the boundary configuration of the fillet is reflected in a set of generalized displacements which characterize the intermediate field.