A considerable number of patients after the Fontan operation require prolonged hospitalization due to significant perioperative morbidities. The early postoperative morbidity can be attributed to elevated pulmonary vascular resistance. We hypothesized that the postoperative outcomes would improve with the routine use of inhaled nitric oxide (iNO) to decrease pulmonary vascular resistance. From January 2015 to November 2017 (Group 1), 37 patients underwent Fontan operation, and from December 2017 to December 2019 (Group 2), 34 patients underwent Fontan operation. All patients in Group 2 received iNO in the immediate perioperative period as part of a standardized postoperative pathway. There was no statistically significant difference in demographics or single ventricle subtype between the two groups. All patients underwent an extracardiac Fontan, and Group 2 had a higher number of fenestration (p< 0.01). Pre-Fontan hemodynamics showed no statistically significant difference in Glenn pressure, transpulmonary gradient, or systemic arterial and venous saturation. Both groups had a median length of stay of 13 days (p = 0.5), median chest tube placement of 7 days (p = 0.5), and there was no statistically significant difference in major complications. Readmission within 1 month of discharge occurred in five patients in Group 1 and six patients in Group 2 (p = 0.7). Routine use of iNO in the early postoperative period after Fontan operation did not reduce the length of stay, chest tube duration, rate of complications, or readmission.