The service lifetime of a laminated structure is one of the major concerns in the design of multilayered material systems. It is limited by the time required for acceptable delamination to propagate, under certain loading conditions, to attain a size perceived to be critical to the stiffness and/or the strength of the structure. This service lifetime could be predicted if the constitutive equation for the delamination rate is known. This paper describes an approach to determine the constitutive equation for delamination under Mode-II creep loading conditions. The approach is based on the principles of linear elastic fracture mechanics and uses an elevated temperature to accelerate the interlaminar fracture at constant loads. The experiments used double-cantilever beam test specimens fabricated as a model system of poly(methyl methacrylate) (PMMA) beams and epoxy adhesive. The effect of temperature on the experimental measurements has been considered. A form of Paris power law is suggested to forecast the service lifetime in terms of temperature, service load and the initial delamination size.