Several studies reveal that positive attitudes towards individuals with a mental illness are correlated with knowledge about mental illness. The aim of this study was to explore and describe psychiatric nurses’ experiences of living next to people with mental health problems. In addition, it sought to identify and describe how they handle situations arising in a neighbourhood where people with a mental illness live. Two men and seven women participated in the study. The constant comparative method of grounded theory was used for data collection and analysis. The process of ‘behaving as a nurse or not’ was identified as a core category. Four subcategories were identified: ‘receiving involuntary information’, ‘to take action or not’, ‘behaving as a mediator in the neighbourhood’ and ‘the freedom of choice’. The findings show that psychiatric nurses with professional knowledge about mental illness have moral concerns about their role as nurses during their leisure time. In conclusion, it is not obvious that psychiatric nurses want to live in the same neighbourhood as persons with a mental illness. However, this study shows that their knowledge about mental illness creates for them a moral dilemma consisting of a conflict between whether to care for these mentally ill persons or to preserve their own leisure time.