Work-related violence is an important problem worldwide, and nurses are at increased risk. This study identified rates of violence against nurses in Minnesota, USA, and their perceptions of the work environment. A sample of 6,300 randomly selected nurses described their experience with work-related violence in the previous year. Differences in perceptions of the work environment and work culture were assessed, based on a nested case-control study, comparing nurses who experienced assault to non-assaulted nurses. Annual rates of physical and non-physical assault, per 100 nurses, were 13.2 (95% CI: 12.2-14.3), and 38.8 (95% CI: 37.4-40.4). Cases were more likely than controls to report: higher levels of work stress; that assault was an expected part of the job; witnessing all types of patient-perpetrated violence in the previous month; and taking corrective measures against work-related assault. Controls versus cases were more likely to perceive higher levels of morale, respect and trust among personnel, and that administrators took action against assault. Nurses frequently experienced work-related violence, and perceptions of the work environment differed between nurses who had experienced physical assault, and those who had not. Employee safety, morale, and retention are particularly important in light of the nursing shortage, and knowledge of nurses' perceptions will assist in tailoring interventions aimed at reducing the substantial risk of physical assault in health care settings.