The Cotonou Agreement is the European Union's most important legal measure in the field of development assistance covering 79 developing countries in Africa, the Caribbean and the Pacific (ACP countries). It empowers the European Union to sanction 'serious cases of corruption' where this corruption is related to economic and sectoral policies and programmes to which the European Union is a significant financial partner. During the negotiations leading to the adoption of the Cotonou Agreement the ACP countries strongly objected to the inclusion of the possibility of sanctioning corruption. In practice the European Union has only sanctioned one single case of corruption under the provision, however. Whereas this does not necessarily mean that the sanctioning clause is without an impact, the fact that sanctions have been imposed in only one situation is a strong indication that its impact is rather limited. It is suggested that more effective means of preventing corruption are considered.