This research discusses some of important models and methodology of inferences relating to life tests and survival studies. Some of the basic important concepts in survival models and the various schemes of censoring are outlined briefly in Chapter 2. Chapter 3 briefly detours to the main concepts of the Bayesian modeling which will be as the basis tool for analyzing the survival models in the remaining chapters of this research. The next three chapters build up Bayesian nonparametric procedure to estimate the parameters of interest in both proportional and additive hazards mode. The author use the WinBUGS software in order illustrates the Bayesian approach in survival models.Throughout the research, the inference procedures are illustrated with numerical examples and with real data sets collected from an insurance company in Egypt.