Interdependence is a core feature of federal regimes, distinct from decentralization (a much more prominent concept). Interdependence is creating intense pressure for coordination. Federal systems vary considerably in how they combine degrees of interdependence and decentralization. Various features generate structural interdependence in regimes. The chapter provides a systematic analysis of possible modes of coordination that government units might adopt in response to coordination pressures. The politics of intergovernmental relations are discussed from the perspective of inter-executive and inter-parliamentary relations. While there is a broad comparative view on interdependence and coordination in federal systems, the cases of Canada, the United States and Switzerland are examined in greater detail.