BACKGROUND: A poor communication with immigrants can lead to inappropriate use of healthcare services, greater risk of misdiagnosis, and lower compliance with treatment. As precise information about communication between emergency physicians (EPs) and immigrants is lacking, we analyzed difficulties in communicating with immigrants in the emergency department (ED) and their possible associations with demographic data, geographical origin and clinical characteristics. METHODS: In an ED with approximately 85000 visits per year, a multiple-choice questionnaire was given to the EPs 4 months after discharge of each immigrant in 2011. RESULTS: Linguistic comprehension was optimal or partial in the majority of patients. Significant barriers were noted in nearly one fourth of patients, for only half of them compatriots who were able to translate. Linguistic barriers were mainly found in older and sicker patients; they were also frequently seen in patients coming from western Africa and southern Europe. Non-linguistic barriers were perceived by EPs in a minority of patients, more frequently in the elderly and frequent attenders. Factors independently associated with a poor final comprehension led to linguistic barriers, non-linguistic obstacles, the absence of intermediaries, and the presence of patient's fear and hostility. The latter probably is a consequence, not the cause, of a poor comprehension. CONCLUSION: Linguistic and non-linguistic barriers, although quite infrequent, are the main factors that compromise communication with immigrants in the ED, with negative effects especially on elderly and more seriously ill patients as well as on physician satisfaction and appropriateness in using services.