To measure the association between the nurse work environment (NWE) and missed nursing care on labor and delivery (L&D) units.L&D units provide a sizable fraction of acute hospital services to a unique population that is a national and global priority. L&D nurses are the frontline providers during labor. Maternal morbidity and mortality may be influenced by the NWE and missed care.This cross-sectional study utilized secondary data from 1,313 L&D staff nurses in 247 hospitals from a four-state nurse survey collected in 2005-2008.Half of nurses missed care (range: zero to 100% across hospitals). Nurses on average missed 1.25 of 10 activities. The most commonly missed activities were comforting/talking with patients and teaching/counseling. In better as compared to poor NWEs, the odds and frequency of missed care were significantly lower.L&D nurses routinely miss necessary nursing activities. Laboring women's psychosocial, comfort, and educational needs are compromised most often, likely impacting quality and outcomes. Nurse communication with colleagues and managers about missed care is warranted.The L&D NWE is modifiable and appears to influence missed care. Managers should discuss missed care with staff and measure their NWE to identify actionable weaknesses.