This contribution analyses the provisions on the Common Security and Defence Policy (CSDP) in the Treaty establishing a Constitution for Europe (EU Constitution), focusing on elements that constitute a further development of the present acquis in this field. It successively addresses the adoption and status of the EU Constitution and the place of the CSDP therein, the objectives, scope and missions of the CSDP, the actors, decision-making, instruments and implementation, capabilities and permanent structured cooperation, financing, enhanced cooperation and cooperation with third States and other international organisation and concludes with some final remarks. The author argues that the commitment to a common defence as a future objective, the mutual defence clause, even with its caveats, the explicitly broader definition of the EU's crisis management missions, the possibility of enhanced cooperation on defence and of entrusting the execution of a mission to a group of Member States, the commitment to improve capabilities, the permanent structured cooperation and the creation of the function of the Union Minister for Foreign Affairs are significant positive developments in the EU Constitution regarding the CSDP. However, he submits that the CSDP still faces several major challenges, in particular some of the provisions concerned are rather ambiguous, a reference to cooperation with NATO is lacking, Member States will have to live up to their commitments and it remains to be seen whether the EU Constitution will enter into force.