In the 1990s environmental policy integration (EPI) became a popular approach to bring about preventive environmental action in key polluting and resource-using sectors. Following the rise of climate change on the political agenda, a similar imperative of climate policy integration (CPI) has emerged. In this chapter, we discuss questions raised by CPI, with some practical examples from EU policymaking. Specifically, we examine whether and how three challenges that have emerged in the context of EPI—the incentive structures of integration; prioritization of objectives; and safeguarding democratic accountability—also hold for CPI. We show that sufficient resources need to accompany CPI, but that the promise of such resources may also lead to ‘re-labeling’ ongoing activities as climate-relevant. We further underline the importance of disaggregating questions of CPI, taking into account the particularities of mitigation and adaptation, as well as those of the different policy sectors with which integration is sought. Finally, we highlight that ensuring the democratic accountability of CPI is particularly challenging in the EU context, where policymakers at one level can defer difficult political tradeoffs between policy goals to other levels of governance.