A life prediction method for ceramic matrix composites is developed. This model is based upon damage mechanics concepts included in the framework of the critical element model. One unique feature of the model is its ability to include general variations of temperature and applied loads as functions of time. A detailed description of application of the model to elevated temperature fatigue is given. In addition, a validation example is presented that includes the combined effects of rupture and fatigue. The comparison with the experimental data is shown to be good, although the result does appear to be dominated by the rupture effect.