The fracture behavior of ceramic matrix composites (CMCs) was investigated using the infrared (IR) thermography nondestructive evaluation (NDE) technique during monotonic and cyclic loadings. The CMCs used for this investigation are continuous Nicalon (silicon carbide fiber) fiber reinforced calsium aluminosilicate (CAS) glass-ceramics matrix composites. During monotonic tension and cyclic fatigue loadings, IR camera was used for in-situ monitoring of temperature evolution, and the temperature changes during testing were measured. Microstructural characterizations using scanning electron microscopy (SEM) were performed to investigate fracture modes and failure mechanisms of Nicalon/CAS samples. In this investigation, the NDE technique and SEM characterization were employed to facilitate a better understanding of damage evolution and progress of Nicalon/CAS composites during monotonic and cyclic loadings.