In the position to make decisions about how much seismic risk mitigation -MMR- to implement and the level of performance required, the need to perform a quantitative analysis of both the benefits that may be obtained as the necessary costs for the implementation of these measures to systematically make a comparison between alternatives in order to make informed decisions, while many authors agree on the use of benefit analysis cost how B/C as a tool to evaluate alternative public investment and social impact. This PhD Thesis is divided into three components: the state of knowledge regarding risk assessment as a method for assessing implementation of MMR benefits; the conceptual, analytical probabilistic assessment for B/C; and application in a real portfolio of public buildings in the city of Manizales in Colombia, with actual project information risk management, where the seismic demand information was generated (threat), characteristics of the elements (exposure) and model behavior (vulnerability), plus the cost analysis for the probabilistic assessment of B/C of the MMR.