In October 2004, UNESCO hosted an International Experts Meeting on "Learning for Work, Citizenship and Sustainability" as a 5-year review of progress since the second International Conference on Technical and Vocational Education (TVET) held in Seoul, Republic of Korea, in April 1999. Discussions led to the conclusion that a new paradigm of both development and TVET was needed. The Director-General of UNESCO, Koichiro Matsuura, began his Opening Address at the 2004 International Experts Meeting on "Learning for Work, Citizenship and Sustainability" by emphasizing the legacy of the Seoul Conference in 1999 and the importance of the two inseparable challenges of sustainable development and building equitable knowledge societies based upon lifelong learning. Mr Matsuura said that "for TVET programmes to be part of the solution and not part of the problem, they must be reoriented so that they contribute to sustainable development worldwide." Accepting the Director-General's challenge, participants at the meeting canvassed a wide range of issues. These discussions resulted in the unanimous adoption of the Bonn Declaration, which summarizes the conclusions of the meeting in the form of advice to the Director-General for consideration and presentation to the Executive Board of UNESCO for further action. This article summarizes the range of ideas on TVET and sustainable development underpinning discussions leading to the Bonn Declaration. It begins with an overview of the broad concept of sustainable development and then discusses the relationships between TVET and the sustainability of the economy, the environment and society. The article concludes by reviewing the many implications for TVET--from pre-workforce learning to learning in the workplace and further training--when it seeks to promote the understanding and practice of sustainable development. (Contains 7 notes.)