Background: Acute gastroenteritis in pediatric patients entails high rates of morbidity and mortality. One of its complications is dehydration, which should be managed carefully. We evaluated the efficacy of metoclopramide in the control of vomiting in children with acute viral gastroenteritis and moderate dehydration. Methods: In this single-blind randomized clinical trial, we randomly assigned children aged 1-7 years with vomiting due to acute viral gastroenteritis to two groups of serum therapy (control) and metoclopramide (intervention). The control group received 5% dextrose water solution along with electrolyte management while the intervention group, in addition to the standard treatment, received 0.1 mg/kg metoclopramide intravenously. Patients were followed for 4 days for the number of vomiting episodes. Findings: 240 children were studied in intervention and control groups (120 in each group). The mean number of vomiting episodes was significantly lower in metoclopramide-assigned patients in all 4 days of the follow up period (P = 0.021, P = 0.007, P = 0.002, and P = 0.001, respectively for day 1 to 4). Conclusion: Although metoclopramide have shown effectiveness in the treatment of vomiting due to acute gastroenteritis, it is suggested performing multicenter studies comparing this drug with other common anti-emetics to allow for a better judgment. Keywords: Gastroenteritis, Vomiting, Dehydration, Metoclopramide, Child