Aim The aim of this paper is to deepen our understanding of how nursing students’ ethical formation is affected by their meeting with vulnerability and suffering in clinical practice. Background In clinical practice the students can learn authentic, caring, and respectful nursing adjusted to the patients’ situation and the practice of distant and general nursing. Reflective processes can support the ethical dimension of nursing, but there is a lack of knowledge concerning the source of students’ ability to maintain and develop their moral integrity. Methods Twenty-four students were interviewed from 2007-2008 to explore the students’ experience of their own vulnerability and suffering in clinical practice and what encouraged or inhibited the students’ ethical formation. The analysis was inspired by Kvale’s three contexts of interpretation, supplemented by Lindseth and Norberg’s method for the interpretation of interview texts. Findings The students found themselves in two different states of vulnerability. One in which they were totally overwhelmed by their vulnerability and the other where their vulnerability became a source of development. Their ideals served as fixed reference points for their ethical formation but the students’ ethical formation may decline in the course of clinical practice. Conclusion Nursing students possess moral sensitivity which is challenged when they meet a clinical practice culture that is incongruent with their ethical ideals. In clinical practice the students seek to attain authenticity and moral integrity by cultivating their own ethical ideals. Nevertheless, clinical practice may expose them to the risk of ethical decline and becoming non-caring nurses.