Export credit guarantee or insurance covers non-payment risks in exports. Many countries have established export credit agencies (ECAs) to promote exports through export credits including export credit guarantee or insurance. Officially supported export credits have brought the concern that they may distort fair competition in international trades. Export credit guarantee or insurance programmes with inadequate premium rates are likely to fall under the prohibited subsidies. ECAs need to understand the requirements of the prohibited subsidies under the Agreement on Subsidies and Countervailing Measures (SCM Agreement). This article will discuss features and functions of export credit guarantee or insurance in international trades. This article will also discuss some issues concerning the elements of a subsidy and illustrated list of prohibited export subsidies with regard to export credit guarantee or insurance by analysing the relevant provisions of the SCM Agreement and WTO Panel or Appellate Body Reports.