The Energy Charter Treaty (ECT) in its Part III which regulates standards of protection guaranteed to foreign investors by the ECT States members, together with the Article 24 of the ECT, constitutes a kind of autonomous investment treatment within the ECT. The ECT provides for a very broad spectrum of standards of protection: fair and equitable treatment; most constant protection and security; prohibition of unreasonable or discriminatory measures; „umbrella clause”; national treatment; most favoured-nation standard and effective means to assert the claims. It can be said that at the time of its drafting the ECT enclosed all standards of protection as recognized in BITs and NAFTA. There have been more than 100 publicly known investment arbitration cases where the ECT was invoked, more than 30 of which concluded by arbitral awards. This comprehensive arbitral practice strongly influences the practice applying other IIAs and vice versa.