This paper describes the reliability analysis model for the Saturn V launch vehicle. A method of quantitative criticality determination is presented wherein six stage and engine reliability prediction models and their associated Failure Effects Analysis Reports are combined to obtain the basis for criticality determination. The derivation of the criticality equation,is also presented. The uses of the Saturn V Reliability Analysis Model, which extend considerably beyond the normal uses of prediction models, include determination of the probabilities of mission success, vehicle survival, and crew survival. The model is further used to assess performance readiness and to identify critical areas requiring management attention.