A formal letter of invitation was sent to potential official participants -- sovereign states and intergovernmental organizations -- through diplomatic channels when the Shanghai Organiser completed the registration procedure with the Bureau of International Expositions at the end of last year. This started the Participants Recruitment Program of Expo 2010.

Non-official participants, such as NGOs, NPOs and corporations, have been invited directly by the Organiser. It is worth noting that, though corporations are non-official participants, they are still advised to notify their respective governments of their intention to participate.

In the first-round of recruitment, official invitation letters were sent to all member states of the United Nations and major international organizations, especially those who are seen to have a strong link with the theme of Expo 2010. In the meantime, the Organiser also sent out invitations to a selected number of NGOs, NPOs and corporations after bilateral consultations.

The official invitees must confirm their participation through diplomatic channels, while the non-official invitees may confirm directly with the Organiser.

The Participation Guidelines have been released in time to assist the decision-making of potential participants and as a ground for discussion with the Organiser.

Once their participation is confirmed, participants will be requested to submit a "Theme Statement" and "Exhibition Project" to the Organiser. The land parcels or exhibition space will be allocated based upon formal application from participants and the consideration of the Organiser, and after a clear Theme Statement is received and approved.