AIMS: Suboptimal healthcare utilisation and lower satisfaction with the patient-doctor encounter among immigrants has been documented. Immigrants' lack of familiarity with the healthcare system has been proposed as an explanation for this. This study investigated whether a systematic delivery of information affected immigrants' knowledge of and satisfaction with the Danish healthcare system. METHODS: A prospective, randomised intervention study of 1158 adult immigrants attending two language schools in Copenhagen was conducted. Two intervention groups received written information or a 12-hour course on the Danish healthcare system, while a control group received nothing. Survey data included self-assessed knowledge, true/false questions on access and questions relating to satisfaction with the healthcare system. Data were linked to socioeconomic registry data. Logistic regression analyses were performed. RESULTS: The course improved knowledge of who to contact in the event of an accident (odds ratio (OR) = 2.67, 95% confidence interval (CI) = 1.56-4.59) but not in the event of illness. Further, it positively affected correct answers for nine out of 11 questions on the healthcare system (varying from OR = 1.87, 95% CI = 1.08-3.24 to OR = 3.11, 95% CI = 1.58-6.11). Written information positively affected correct answers for three out of 11 questions, but negatively affected one out of 11 compared with the control group. Neither intervention affected immigrants' satisfaction with the healthcare system. CONCLUSIONS: Knowledge of the healthcare system is necessary for optimal healthcare-seeking behaviour. The results may form the basis of national and international changes in immigrant reception and optimise immigrants' contact with the healthcare system.