BACKGROUND: This study aimed to compare the gastric fluid volume (GFV) in children who fasted 1 versus 2 hours using ultrasound, after ingestion of a defined volume of clear fluid. METHODS: Children scheduled for elective surgery were enrolled in this randomized, double-blinded, controlled trial. After receiving 3 mL kg–1 clear fluid, participants were randomized to have a gastric ultrasound after fasting for either 1 hour (1-hour group, n = 116) or 2 hours (2-hour group, n = 111). Our primary outcome was the GFV. Other outcomes included the antral cross-sectional area, frequency of high risk and low risk of aspiration, and qualitative grading for the gastric antrum. RESULTS: Two hundred and twenty-seven children were available for final analysis. The median (Q1–Q3) GFV was higher in the 1-hour group versus the 2-hour group (0.61 [0.41–0.9] mL kg–1 vs 0.32 [0.23–0.47] mL kg–1; P value = .001). None of the study groups had GFV ≥1.5 mL kg–1. The frequency (%) of GFV ≥1.25 mL kg–1 was comparable between both groups (2 [1.7%] vs 0 [0%], P value = .165). However, the frequency of GFV ≥0.8 mL kg–1 was higher in 1-hour group than in 2-hour group (34.5% vs 4.5%), and grade 2 antral grading score was 56.9% in 1-hour group vs 0.9% in 2-hour group (P value <.001). CONCLUSIONS: In healthy children scheduled for elective surgery receiving 3 mL kg–1 clear fluid, the median GFV after 1-hour fasting was double the volume after conventional 2-hour fasting. These findings should be considered whether weighting the risk/benefit of a liberal approach to preoperative fasting versus the risk of pulmonary aspiration.