This paper is concerned with aspects of responsibility in Norwegian public health nursing. Public health nursing is an expansive profession with diffuse boundaries. The Norwegian public health nurse does not perform 'hands on' nursing, but focuses on the prevention of illness, injury, or disability, and the promotion of health. What is the essence of ethical responsibility in public health nursing? The aim of this article is to explore the phenomenon based on the ethics of responsibility as reflected upon by the philosopher Emanuel Levinas (1906-1995). From an ethical point of view, responsibility is about our duty towards the Other, a duty we have not always chosen, are prepared for, or can fully explain; but it is nevertheless a demand we have to live with. Interviews with five experienced Norwegian nurses provide the empirical base for reflection and interpretation. The nurses share stories from their practice. In interpreting the nurses' stories, the following themes emerge: personal responsibility; boundaries; temporality; worry, fear, and uncertainty; and a sense of satisfaction. As the themes are developed further, it becomes apparent that, despite their diversity, they are all interrelated aspects of ethical responsibility. Responsibility for the Other cannot be avoided, ignored, or transferred. The nurses' responsibility is personal and infinite. Levinasian ethics can help nurses understand the importance of accepting that being a responsive carer can involve not only contentment in the predictable, but also the fear, worry, and uncertainty of the unpredictable.