Do mergers favor or kill innovation? In dynamic economies, merger could result in both pro-competitive dynamic efficiencies and potential competitive dynamic harm that may arise as a result of the future conduct of the merged firm. This trade-off involves: (i) the merged firm and its competitors’ ability and incentive to invest and innovate, (ii) the merged firm and its competitors’ ability and incentive to enter or exit a market, (iii) Dynamic price effects resulting from changes in innovation, investment, entry, or exit. The lecture is aimed at discussing both the theoretical and empirical economic literature that have recently contributed to the analysis of this hot debated issue.