Excessive nursing workload is a known safety issue. This study examined whether nurse workload in the neonatal intensive care unit affected the quality of nursing care. Investigators measured workload using patient–nurse ratios, taking into account patient acuity, and a convenience sample of nurses also reported their perceived workload. Participating nurses were asked to report the care they provided, and missed care was defined as self-reported failure to provide any of 11 prespecified essential elements of nursing care. The authors identified a consistent association between perceived workload and missed care, suggesting that nurses' own assessments of their workload should be a safety consideration. A PSNet perspective explores how missed nursing care may explain the association between low nurse staffing levels and increased mortality in hospital patients.