People experiencing long-term physical conditions are predominantly cared for within primary care settings by nurses. These patients are two-to-three times more likely to develop mental health problems as a result of the detrimental impact of their illness on their physical and social functioning. They are also more likely to disclose mental health issues to nurses working in primary care — therefore, general practice nurses (GPNs) need to be able to recognise both mental distress and mental illness to ensure that their patients receive appropriate assessment, care and management. This article discusses the prevalence of mental health problems in patients with long-term physical conditions and how nurses in primary care settings can recognise, assess and support them.