The Emergency Use Authorization(EUA) is a new tool for timely and practical use of unapproved diagnostic products of some infectious diseases as one of the rapid countermeasure responses to infectious disease threat. Recently, Korean Centers for Disease Control and Prevention started the EUA to make available diagnostic tools in civil to identify and respond to serious infectious diseases in collaboration with Ministry of Food and Drug Safety. This article describes the EUA systems in U.S. and WHO and introduces the first two applications of EUA in Korea – Zika virus and MERS – which were approved in 2016 and finally, discusses the prospective of this system.