Since its creation in 1958, the European Social Fund (ESF) has played a major role in supporting the development of vocational training in the Member States. However, compared to other, more recently launched, EU programmes and initiatives in the area of education and training, the ESF has not made a significant contribution to the debate about European cooperation in this field. This article argues that the ESF has made a mistake in this respect. It also seeks to illustrate and analyse the important changes that the ESF has undergone over the years in addressing the issue of vocational education and training (VET) and to demonstrate that it has substantial resources, in terms of money and experience, that can be used to adapt education and training systems to labour market requirements and to the needs of a knowledge-based economy. The article places a deliberate, though not an exclusive, emphasis on vocational education and training for young people and on the extension of transnational cooperation within the framework of the ESF. (Contains 12 notes.)