This volume contains the papers presented at the Second International Sym- sium on Algorithmic Game Theory (SAGT 2009), which was held on October 18-20, 2009, in Paphos, Cyprus. This event followed the ?rst, very successful SAGT symposium, which took place in Paderborn, Germany, last year. The purpose of SAGT is to bring together researchers from computer s- ence, economics and mathematics to present and discuss originalresearchat the intersection of algorithms and game theory. It has been intended to cover all important areas such as solution concepts, game classes, computation of equil-...