BACKGROUND: Substantial variability exists in the care of febrile, well-appearing infants. We aimed to assess the impact of a national quality initiative on appropriate hospitalization and length of stay (LOS) in this population. METHODS: The initiative, entitled Reducing Variability in the Infant Sepsis Evaluation (REVISE), was designed to standardize care for well-appearing infants ages 7 to 60 days evaluated for fever without an obvious source. Twelve months of baseline and 12 months of implementation data were collected from emergency departments and inpatient units. Ill-appearing infants and those with comorbid conditions were excluded. Participating sites received change tools, run charts, a mobile application, live webinars, coaching, and a LISTSERV. Analyses were performed via statistical process control charts and interrupted time series regression. The 2 outcome measures were the percentage of hospitalized infants who were evaluated and hospitalized appropriately and the percentage of hospitalized infants who were discharged with an appropriate LOS. RESULTS: In total, 124 hospitals from 38 states provided data on 20 570 infants. The median site improvement in percentages of infants who were evaluated and hospitalized appropriately and in those with appropriate LOS was 5.3% (interquartile range = 22.5% to 13.7%) and 15.5% (interquartile range = 2.9 to 31.3), respectively. Special cause variation toward the target was identified for both measures. There was no change in delayed treatment or missed bacterial infections (slope difference 0.1; 95% confidence interval, 28.3 to 9.1). CONCLUSIONS: Reducing Variability in the Infant Sepsis Evaluation noted improvement in key aspects of febrile infant management. Similar projects may be used to improve care in other clinical conditions.