Objective To explore and classify the subjective opinions of nurses on whistle- blowing, and identify the subjective characteristics of each type. Methods This study applied Q -methodology, protocols which could determinate subjective opinions of nurses on histle-blowing were set up and underwent interview investigation, data of the interviews went through Q-factor analysis. Results Most nurses had a positive attitude toward whistle - blowing because it could prevent any nursing activity not based on expertise and professional ethics from causing disadvantages for patients. At the same time, however, they requested the creation of a legal framework in which whistle-blowing was done in a way to increase trust among colleagues. Meanwhile, some nurses showed resistance to whistle - blowing. Conclusions Whether whistle - blowing can reach its aims depends on nurses' attitude toward it. Most Korean nurses support whistle-blowing. Nursing activity not based on expertise and professional ethics and causing disadvantages for patients can be avoided if a legal framework is established for whistle-blowing.