Zooming in on the serving European Union (EU) Member States and exploring the legal parameters defining regional actorness both directly and indirectly, this article analyzes the EU's representation at the United Nations (UN) Security Council. Looking at the theory and practice behind Articles 52, 23 and 103 of the UN Charter, we shed fresh light on the only provision in the European Treaties that explicitly referred to the UN Security Council, i.e. the former Article 19 of the EU Treaty. We define that provision as a regional interpretation of Article 103 of the UN Charter and discuss its implementation in day-to-day decision-making, especially as for economic and financial sanctions measures. Hereby, we focus on the negotiations leading to UN Security Council Resolution 1822(2008).