This article examines state intervention in the energy sector under the EC Treaty. The analysis focuses upon Articles 37, on state trading monopolies, and 90, on public undertakings, the conferment of exclusive rights and undertakings entrusted with the operation of services of general economic interest. All these forms of business organisation are very common in the energy sector. The Commission's wish to introduce more competition in the public utilities sector is well served by the application of the Treaty rules on a case-to-case basis. Secondarily, legislation has also been adopted for the energy sector pursuant to Article 100A EC. There is considerable public debate on new proposals for directives which aim at further liberalisation in the energy market.