觀察目前服務貿易總協定(General Agreement on Trade in Services, GATS)案件，涉及GATS第2條最惠國待遇與第17條國民待遇之數量佔有極高比例。適用第2條與第17條規定時，須先認定案件之服務或服務供給者符合「同類服務與服務供給者」，唯有確定會員系爭措施規範對象與其他會員之服務或服務供給者，抑或是國內服務或服務供給者為同類服務或同類服務供給者，方能檢驗會員系爭措施有無對同類服務與服務供給者為差別待遇，因此，「同類服務與服務供給者」乃第2條與第17條之先決要件，具有極關鍵性地位。 由於服務具有不可識別性與不可儲存性，欲判斷服務或服務供給者間是否為同類服務或服務供給者有相當困難度，加上GATS原文對「同類服務與服務供給者」之服務與服務供給者係以「和」為連接詞，引發學者與會員就如何解釋「同類服務」與「同類服務供給者」適用關係之爭議；甚而，GATS第1條第1項將規範之服務貿易區分為四種不同供給模式，以不同供給模式提供之服務或服務供給者是否會因供給模式而被認定為不同類服務或不同類服務供給者，亦是「同類服務與服務供給者」與GATS規範架構之適用爭議；此外，GATS第2條與第17條「同類服務與服務供給者」之適用範圍，應如何與其規範目的為相呼應之解釋，亦是極具挑戰性之課題。由此可見，「同類服務與服務供給者」存在諸多適用上爭議，尤其在爭端解決小組與上訴機構尚未就「同類服務與服務供給者」適用爭議提出說明之情形，研究「同類服務與服務供給者」乃刻不容緩之事。 鑑於世界貿易組織(World Trade Organization, WTO)之爭端解決小組與上訴機構對關稅與貨品貿易總協定(The General Agreement on Tariff and Trade, GATT)與WTO「同類產品」已大致建立認定方法，並對「同類產品」之適用爭議提出見解，GATS於談判過程中曾有會員建議以「同類情形」作為適用最惠國待遇與國民待遇之規範要件，本文除論述GATS涉及「同類服務與服務供給者」案件之爭端解決小組與上訴機構見解，亦分析GATT/WTO「同類產品」案件與北美區域自由貿易協定(North American Free Trade Agreement, NAFTA)牽涉「同類情形」案件之判決經驗，為認定GATS「同類服務與服務供給者」與相關適用爭議找尋可能之解決方案。 / Observing recent GATS(The General Agreement on Trade in Services)cases, there are almost quart cases relevant to non-discrimination regulations of GATS, Article 2 and 17.As applying to non-discrimination regulations of GATS, before examining whether Members’domestic measures have discriminated effects to block the international services market, applicants, the Panel or Appellate Body need to determine whether the services and services suppliers concerned are ‘like services’or ‘like service supplier’. For‘like services and service suppliers’being a crucial requirement of non-discrimination regulations in GATS, researching how this requirement is applied to dispute settlement cases is an important mission to GATS. Actually, the vital issues of ‘like services and service suppliers’include: how to determine the ‘like services’and ‘like service suppliers’, how to decide whether the services and service suppliers through different supply modes are like services and like service suppliers, and how to interpret the application between ‘like services’ and ‘like service suppliers’. Moreover, interpreting the coverage of ‘like services and service suppliers’ under GATS is also a tough issue. Notwithstanding the requirement of non-discrimination principles -‘like services and service suppliers’rises many applied issues, there are no regulations of GATS to define the meaning of ‘like services’ and ‘like service suppliers', and no regulations or explanatory footnotes to clarify the applied problems of ‘like services and service suppliers’. The only way for Members or scholars to realize how to apply to this requirement or to determine ‘like services and like service suppliers’ is to analyze relevant judgments of dispute settlement cases relevant. However, WTO dispute settlement panel or appellate body did not analyze the relevant applied issues of‘like services and services suppliers’, and not resolve those applied issues completely. For resolving those issues of ‘like services and service suppliers’, this article make relevant material divided into four parts. First of all is to discuss what issues‘like services and service suppliers’arises, and what the factors cause ‘like services and services suppliers’ is hard to be practiced. The second part is referring to the judgments of dispute settlement panel and appellate body in GATT(The General Agreement on Tariff and Trade)/WTO cases regarding the applications of ‘like products’. Then, referring to the judgments of NAFTA(The North American Free Trade Agreement) dispute settlement organization in NAFTA cases considering ‘like circumstances’. Finally, this article not only advances the resolutions to resolve those issues of ‘like services and service suppliers’, in order to improve the practice of this requirement, but also recommends several suggestions about modifying the content of this requirement.