In this article we use a linear elastic fracture mechanics approach to characterize the adhesive performance of two commercially available pressure-sensitive adhesives (PSAs). An axisymmetric adhesion test involving the contact of a spherical indenter with a thin adhesive layer is used to generate "tack" curves for both adhesives. These curves describe the relationship between the normal loads and displacements during the test. Adhesive failure is understood in terms of crack propagation at the indenter/adhesive interface. We investigate the effects of adhesive layer thickness and crosshead velocity on the tack curves. Using fracture mechanics equations developed for thin layers, we show that the energy release rate is a unique function of the crack velocity for a given adhesive. Based on the tack curves and energy release rates, we discuss the coupling of the bulk and interfacial properties that produce the large adhesion energies typical of pressure-sensitive adhesives.