Approximately one million patients in the Netherlands and 27-36 million patients in Europe have one of the 5,000-8,000 known rare diseases. These patients often do not receive the care they need or with a substantial delay from diagnosis to treatment. As of March 2017, 24 European Reference Networks (ERNs) were launched with the aim to improve the care for these patients through cross-border healthcare, where in principle the knowledge travels and not the patient. It is expected that through the ERNs, European patients with a rare disease get more often and more quickly access to expert care and that it will accelerate guideline development and research. In each of the 24 ERNs, one or more Dutch expertise centres for rare diseases participate, and 5 ERNs are coordinated by centres from the Netherlands.