OBJECTIVES: Reduce postoperative hypothermia by up to 50% over a 12-month period in children’s hospital NICUs and identify specific clinical practices that impact success. METHODS: Literature review, expert opinion, and benchmarking were used to develop clinical practice recommendations for maintaining perioperative euthermia that included the following: established euthermia before transport to the operating room (OR), standardized practice for maintaining euthermia on transport to and from the OR, and standardized practice to prevent intraoperative heat loss. Process measures were focused on maintaining euthermia during these time points. The outcome measure was the proportion of patients with postoperative hypothermia (temperature #36°C within 30 minutes of a return to the NICU or at the completion of a procedure in the NICU). Balancing measures were the proportion of patients with postoperative temperature .38°C or the presence of thermal burns. Multivariable logistic regression was used to identify key practices that improved outcome. RESULTS: Postoperative hypothermia decreased by 48%, from a baseline of 20.3% (January 2011 to September 2013) to 10.5% by June 2015. Strategies associated with decreased hypothermia include .90% compliance with patient euthermia (36.1–37.9°C) at times of OR arrival (odds ratio: 0.58; 95% confidence interval [CI]: 0.43–0.79; P, .001) and OR departure (odds ratio: 0.0.73; 95% CI: 0.56–0.95; P = .017) and prewarming the OR ambient temperature to .74°F (odds ratio: 0.78; 95% CI: 0.62–0.999; P = .05). Hyperthermia increased from a baseline of 1.1% to 2.2% during the project. No thermal burns were reported. CONCLUSIONS: Reducing postoperative hypothermia is possible. Key practices include prewarming the OR and compliance with strategies to maintain euthermia at select time points throughout the perioperative period.