This integrative review is on emergency department nurses' perceptions on mental health patients waiting for placement. Seven articles met inclusion criteria. Themes included violence and patient safety, psychiatry and mental health support, attitudes and beliefs, education and training, emergency department workflow and environment, and long waits in the emergency department. Future research focusing on the care of mental health patients boarding in the emergency department is needed to address this issue. A limitation was that there were no focused studies on mental health boarders in the emergency department, and information had to be gleaned from articles on caring for mental health patients in emergency departments in general.