In hospitals, nurses provide patient care around the clock, but the impact of night staff characteristics on patient outcomes is not well understood. The aim of this study was to examine the association between night nurse staffing and workforce characteristics and the length of stay (LOS) in 138 Veterans Affairs (VA) hospitals using panel data from 2002 through 2006. Staffing in hours per patient day was higher during the day than at night. The day nurse workforce had more educational preparation than the night workforce. Nurses’ years of experience at the unit, facility, and VA level were greater at night. In multivariate analyses controlling for confounding variables, higher night staffing and a higher skill mix were associated with reduced LOS.