The mechanical properties of carbon fiber/polyetheretherketone (CF/PEEK) composites have been characterized for structural applications. Stiffness and strength properties were measured on unidirectional laminates in tension, compression, and flexure, enabling the elastic constants for the material to be determined. Stiffness and strength were measured on multidirectional lay-ups in tension. The effect of temperature on strength was examined for fiber- and matrix-dominated lay-ups. Toughness was assessed using fracture mechanics techniques, instrumented falling weight impact tests, and postimpact compression tests to obtain both intrinsic and comparative toughness. Creep and fatigue properties were characterized on fiber- and matrix-dominated lay-ups. The evaluations provide a property data base for CF/PEEK composites.