Background: Classical rapid sequence induction and intubation (RSII) is used to reduce pulmonary aspiration, but it increases the risk of hypoxemia. Apneic oxygenation (ApOx) has been studied to prolong safe apneic time, and to decrease the incidence of hypoxemia in adults. The aim of this study was to investigate the effectiveness of ApOx via low-flow nasal cannula to reduce the incidence of hypoxemia in pediatric rapid sequence induction.Methods: This prospective single-blind randomized controlled trial included patients aged 0-7 years, American Society of Anesthesiologists (ASA) physical status 1 to 3, who underwent elective or emergency surgery under general anesthesia with rapid sequence induction during February 2020 to March 2021.Participants were randomized to the ApOx group or the classical rapid sequence induction group. The ApOx group received oxygen flow via regular nasal cannula, as follows: 1 liter per minute (LPM) in age 0-1 month, 2 LPM in age 1-12 months, and 4 LPM in age 1-7 years. The classical group did not receive oxygen supplementation during intubation. The primary outcome was the incidence of hypoxemia, defined as oxygen saturation (SpO 2 ) ≤92%.Results: Sixty-four participants were recruited. The incidence of hypoxemia in both groups was 8 of 32 participants (25%) (P=1.000). Among desaturated patients, the median time to desaturation was 29.5 and 35 seconds in the ApOx and classical groups, respectively (P=0.527). The median lowest SpO 2 was 91% and 88.5% in the ApOx and classical groups, respectively (P=0.079). In non-desaturated patients, the median time to successful intubation was 40.5 and 35.5 seconds in the ApOx and classical groups, respectively (P=0.069). Conclusions:In this small sample study, ApOx using age-adjusted low-flow nasal cannula was ineffective for reducing the incidence of hypoxemia in pediatric RSII.