Background & Aims: Secondary traumatic stress (STS) can be described as an occupational hazard for those providing care to victims of trauma. In health professions, there are times when individuals are in constant and close contact with trauma survivors and experience significant emotional disturbance, thereby becoming indirect trauma victims. Some of STS symptoms include increased negative emotions, the existence of annoying thoughts, failure to separate work from personal life, decreased frustration tolerance, increased anger, depression, disabling and selfish behaviors, fear of working with certain people, self-blame, keeping on one's toes, decreased sense of competence at work, lack of goal, lack of enjoying the profession, decreased performance in unprofessional conditions, and loss of hope in life. Numerous factors such as environmental factors (e.g., work style, perceived organizational support, workload, client needs, and relationships with colleagues) and individual factors (e.g., level of education, level of experience, and coping styles) contribute to STSS. Nurses in psychiatric wards are faced with severe and complicated challenges in the workplace to provide mental health care. In addition, they should be aware of the risk factors and symptoms of STS. Nurses need to skillfully develop resilience in order to cope with occupational problems and ensure their mental health since resilience and the associated behaviors help overcome negative experiences and turn them into positive experiences. The present study aimed to investigate STS and resilience in the nurses at the psychiatric medical centers affiliated to Tehran University of Medical Science in 2018. Materials & Methods: This cross-sectional, descriptive study was conducted on 200 nurses working in the psychiatric medical centers affiliated to