AbstractE-glass fiber-reinforced polymer (FRP) composite wind turbine blades are nonbiodegradable, and their end-of-life recycling solutions are limited. Research on reusing and repurposing applications, where minimal amounts of refabrication are needed, is being conducted to address this issue. To design new structures from decommissioned blades, their as-received mechanical and physical properties are needed. Even though some long-term property data for FRP composites exist in the literature, very little actual data for the as-received residual properties of decommissioned blades have been reported. The current work is aimed at developing a methodology to obtain as-received material property data for decommissioned wind turbine blades that are being proposed for use as second-life structural components. In this paper, details of the methods used and the test results for the key physical and mechanical properties of glass FRP material specimens extracted from the spar cap of a decommissioned 1.5-MW GE37 wind turbine blade are reported (the blade is from a General Electric 1.5 MW turbine which is known as a GE37 blade), including burnout testing for constituents’ weight and volume fractions as well as fiber architecture and tension, compression, and shear testing in the longitudinal and transverse material directions. Comparisons between test results of other investigators and the experimental data obtained show promising strength and stiffness retention levels of the material for different properties. The results show that structural integrity still exists for the tested composite materials and no deterioration, crack propagation, or delamination was observed in the materials due to the cyclic loading levels experienced in their first life.