Fatigue damage accumulation and failure modes of several unidirectional and angle-ply SCS-6 fiber-reinforced titanium matrix composites are reviewed. The fatigue damage characteristics of the notched and unnotched composites were classified using several schematic diagrams based upon the constituent's properties and loading conditions. Quantitative relationships between the microstructural damage and stiffness reduction were also established. A shear-lag model incorporating a damage function (which involved the cracking density and length, fiber/matrix frictional stress, and debonding length) was also used to predict residual stiffness of the composites.