Using the National Institute for Occupational Safety and Health job stress questionnaire, the authors examined psychiatric nurses' intention to leave their job in relation to their perceived risk of assault, their job satisfaction, and their supervisory support. Respondents were 1,494 nurses (response rate, 76.5 percent) employed in 27 psychiatric hospitals in Japan. Forty-four percent reported intention to leave their job, and 89 percent of those perceived a risk of assault. Younger age, fewer previous job changes, less supervisory support, lower job satisfaction, and more perceived risk of assault were significant predictors of intention to leave. Organizational efforts are necessary to retain frontline professional staff.