This article is Part I of a three part article. Part I describes work‐related experiences of anger of female registered professional nurses(N =9)who participated in phenomenological interviews. Participants ranged in age from 29 to 56 and had practiced nursing for a period of 7 to 34 years. Nurses described being “under assault” in a hostile environment. Military metaphors and similes permeated all the interviews. Subtheme of “under assault” included scapegoating, disrespectful treatment, and lack of support. Anger was a weapon used by the nurse to defend or advocate for patients or self, as well as to attack doctors, peers, patients, and self. Factors within the self such as control versus powerlessness influenced nurses’ anger experience and expression. Infighting within the profession prevents mobilization of resources to confront the larger issues of healthcare reform. Nurses must reframe anger as a constructive means of empowerment, rather than a weapon to defend against assault. Part II addresses anger experiences of male registered nurses, and Part III provides recommendations for channeling anger con