An experimental method is presented to measure the adhesive strength between spherical inclusions and transparent host matrices, The technique was developed to measure reliably the adhesive strengths between particles and resin matrices. Commonly used adhesion tests possess ill-defined stress concentrations inherent in their design that make them unsuitable for the determination of true adhesive strengths. The procedure developed here involves embedding a sphere of the candidate particle material in the contoured neck portion of a cylindrical epoxy bar (or that of other transparent resin). The decohesion of the sample from the epoxy is observed as the bar is strained in tension. The radial stress at the poles leading to decohesion is then determined by means of a numerical solution of the deformation problem. Adhesive strength data were obtained from a number of epoxy specimens containing particles of Delrin, Nylon, polycarbonate and silica glass, and are presented here and discussed in relation to particle-surface pre-treatments.