In most cases, prior to being admitted into an international organisation as a conference interpreter, candidates need to be tested. The Language Competitive Examination (LCE) is the test that the United Nations organises to assess the level of proficiency of candidates and decide who possesses the necessary skills to work at the UN. Since 2001, an increasing number of examinations have been held to establish a roster from which to cover present and future vacancies. Despite the large number of applicants, very few of them actually pass. One reason might be that LCE speeches present specific challenges that candidates have to master beforehand in order to pass the examination. An analysis of LCE procedure was carried out to shed light on the main features of the LCE. The results show that UN topics, speed and accents are the main challenges that candidates must be aware of if they are to prepare appropriately. These findings are corroborated by a survey targeted at UN staff interpreters, who suggest that the challenge lies in the very modality tested at the LCE, which is simultaneous interpreting.