The chapter aims to show how ‘big data’ transforms the field of political communication. Political communication has entered a new phase of political marketing, in which big data is used to launch sophisticated micro-targeting initiatives. The chapter shows that political campaigns cannot rely entirely on data technology and big data consultants to produce effective campaigns. Although there may be definite advantages to using big data in campaigns, there are also clear limits to the use of data. Furthermore, some critics express democratic concerns. They argue that the use of big data in election campaigns creates a kind of elitist ‘managerial democracy’ on behalf of deliberative democracy. The chapter concludes that the successful use of big data in political communication depends on a comprehensive and democratic co-evolution of the institutional logics behind big data.