Scholars and practitioners agree that dealing with complex policy problems poses a challenge of policy integration. In other words, we need to understand how to integrate new problems into existing policies and create linkages between existing policy systems. Up to now, the scientific literature has focused on policy integration predominantly from a policy design perspective. This special issue puts the focus on political aspects of the policy integration process. The papers examine the politics of policy integration from a theoretical and empirical perspective. The results underline the importance of issue salience, political leadership, actor consultation and policy implementation for the political process toward more policy integration.