This study aims to unveil the process of whistleblowing. Two nursing staff members who worked in a psychiatric hospital convicted of large-scale wrongdoing were interviewed. Data were analyzed using a modified grounded theory approach. Analysis of the interviews demonstrated that they did not decide to whistleblow when they were suspicious or had an awareness of wrongdoing. They continued to work, driven by appreciation, affection, and a sense of duty. Their decision to whistleblow was ultimately motivated by firm conviction. Shortly after (...) whistleblowing, wavering emotions were observed, consisting of a guilty conscience, fear of retribution, and pride, which subsequently transformed to stable emotions containing a sense of relief and regret for delayed action. It is necessary for nurses to recognize that their professional responsibility is primarily to patients, not to organizations. Nurses should also have professional judgment about appropriate allegiance and actions. (shrink)