Background: Dental anxiety often poses a significant barrier to effective dental care in pediatric patients. This study evaluated the efficacy and safety of oral midazolam at two different doses for sedation and amnesia in preschool children undergoing dental procedures under 30 min, including primary teeth extraction, root canal treatment, dental filling, and stainless-steel crown. Methods: This prospective, double-blind, randomized controlled trial included 80 children aged 3-6 years with dental anxiety (Types 1 and 2 of the Frankl Behavior Rating Scale) at the National Hospital of Odonto-Stomatology, Hanoi. following the CONSORT guidelines. Participants were randomly assigned to receive oral midazolam at 0.3 mg/kg or 0.6 mg/kg. Sedation efficacy, onset time, procedure duration, cooperation level (Houpt Behavior Rating Scale), recovery time, and amnesia at 12 h, 24 h, and 1 week, as well as adverse events, were recorded and analyzed. Results: Both midazolam doses were effective for sedation (0.3 mg/kg: 95% vs. 0.6 mg/kg: 100%, p = 0.49). The higher dose (0.6 mg/kg) provided significantly longer effective procedural time (27.3 +/- 4.1 min vs. 20.3 +/- 4.0 min, p < 0.001) and better patient cooperation (95% vs. 78.9%, p = 0.045), but slightly prolonged recovery time (34.6 +/- 4.6 min vs. 31.8 +/- 4.4 min, p = 0.008). Both doses produced similar amnesic effects, with approximately 90% anterograde amnesia at 12 h post-procedure. Adverse events were minimal and mild. Conclusions: Both 0.3 mg/kg and 0.6 mg/kg doses of oral midazolam are safe and effective for sedation and amnesia in preschool children undergoing dental procedures. While the 0.6 mg/kg dose provides better procedural cooperation and prolonged sedation, it also requires a slightly longer recovery time