In many countries, including the United States, the civil infrastructure is no longer within desired levels of performance and safety. Decisions regarding infrastructure systems should be supported by an integrated reliability-based life-cycle multi-objective optimization framework by considering, among other factors, the likelihood of successful performance and the total expected cost accrued over the entire life-cycle. The primary objective of this paper is to highlight recent accomplishments in the life-cycle performance assessment, cost and optimization of aging structures and infrastructures under uncertainty. Applications to life-cycle management of existing bridges are presented and discussed.