Adhesion between a rigid flat cylindrical punch and an elastic layer has been investigated. FE analysis was employed to determine the layer stiffness. Linear elastic fracture mechanics was then used to determine the energy release rate, G(a), per unit of bonded area for a circular debond propagating inwards from the edge of the punch. The calculations showed a strong effect of Poisson＇s ratio for thin layers, small departures from complete incompressibility causing large reductions in stiffness and hence in detachment force. Experiments were performed with an aluminum punch adhered to a rubber layer using a rubber-based adhesive. The ratio of punch radius to layer thickness was varied over the range 0.07 to 3.3. Detachment forces were measured and compared with calculated values. Reasonable agreement was obtained for thick layers but not for thin ones, possibly because of a change in the mode of failure.