As we get better at recognising, diagnosing and managing inherited metabolic diseases, we create a set of new challenges. Patients with classical IMDs are surviving longer, so adult physicians looking after IMD patients are being presented with sicker patients who are more likely to have metabolic decompensations. We are also learning more about the natural history of these disorders and recognising that there are long-term complications in patients who survive the acute presentation. There is still much to learn about how older patients should be managed in order to minimise the risk of complications and maximise quality of life. A successful transition process to adult care is crucial in this respect. In addition, as diagnostic tests become more generally available, it is becoming clear that there are attenuated forms of many of these diseases which often look very different to the classical, infantile-onset conditions. In this course, aimed at both paediatric and adult metabolic specialist and traineess, we will discuss these issues and address a number of specific controversies in the management of older patients with IMDs.