Patient safety is an ongoing challenge in the design and delivery of health-care services. As registered nurses play an integral role in patient safety, further examination of the link between nursing work and patient safety is warranted. The present study examines the relationship between nurses' perceptions of job demands and nurses' perceptions of patient safety. Structural equation modeling is used to analyze the data collected from a survey of 430 registered nurses at two community hospitals in the USA. As hypothesized, nurses' perception of patient safety decreases as the job demands increase. The level of personal control over practice directly affects nurses' perception of the ability to assure patient well-being. Nurses who work full-time and are highly educated have a decreased perception of patient safety, as well. The significant relationship between job demands and patient safety confirms that nurses make a connection between their working conditions and the ability to deliver safe care.