Negotiations among the current participants (i.e. Canada, the EU, Japan and the Russian Federation) started in 2001 towards an agreement for the joint implementation of ITER. Other countries (i.e. USA and China) are considering joining. All the countries, which provide the financial support for the construction and operation of the machine, will have a role in the use of ITER. All the knowledge derived by the exploitation of the experiments will be shared among them. Bilateral agreements with other countries could be used for their participation in ITER experiments.