Abstract: The World Trade Organization (WTO) law provides for rules and disciplines on international trade in services, based on the principles of  non-discrimination. One of these principles is the Most – Favoured – Nation Treatment (MFN), according to which WTO members shall accord immediately and unconditionally to services and service suppliers of any other member treatment no less favourable than that it accords to like services and service suppliers of any other country (Art.II par. 1 GATS). A three – tier test of consistency is set out to determine whether there is a violation of the MFN treatment obligation under Art. IT, par. 1 of GATS: whether the measure at issue is a measure covered by the GA TS; whether the service or service suppliers concerned are “like services” or “like service suppliers”; whether less favourable treatment is accorded to the service or service suppliers of a member. The article analyzes the three conditions and gives reference to the Panel and Appellate Body relevant reports in the field.

Key-words: most-favoured-nation treatment, trade in services, like services, like services suppliers.