Diabetes is a global health problem, with a challenging epidemiology. It is one of the major health problems affecting countries around the world, particularly the UK (World Health Organization [WHO], 2006; Department of Health [DH], 2006b). It is also a growing public health threat in the US (Mokdad et al, 2001). As a result, diabetes has become an important public health issue, prompting the WHO and International Diabetes Federation (IDF) to adopt the theme 'Diabetes for Everyone' for World Diabetes Day 2006. In 2007, on World Diabetes Day, the United Nations also launched its 'Living with Diabetes at School' campaign, in response to the growing diabetes 'epidemics' (Diabetes UK, 2007). This article provides an overview of diabetes mellitus and its acute- and long-term management, including definition, aetiology, pathophysiology, classification, signs, symptoms and complications. The role of the nurse in providing patient-centred care for people with diabetes is emphasized.