Probabilistic methods have been widely employed in many areas of engineering and science, especially civil engineering, electrical engineering, statistical physics and information sciences. They are also ideal for damage detection and reliability analysis of structures, given different types of uncertainty in these problems. This book presents some recent developments on the use of probabilistic methods to ensure safety of structures. Following a review of the state of the art in this field, the book introduces an artificial neural network design algorithm using Bayesian method and application in damage detection; a probabilistic approach for multiple cracks identification in beams; and reliability analysis of single-degree-of-freedom elastoplastic system using important sampling method.