Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is one of the most common fatty acid oxidation disorders. The choice of anesthetics and blood glucose management are crucial to prevent metabolic decompensation. A 5-year-old Japanese boy with MCAD deficiency was scheduled to undergo surgery for an inguinal hernia. Glucose was continuously infused perioperatively, and his glucose concentrations were within the normal range. Anesthesia was induced and maintained with remimazolam, remifentanil, and intermittent rocuronium. No metabolic decompensation was observed. This case indicates the importance of a continuous intravenous glucose infusion, and that remimazolam can be the first-line anesthetic for a patient with MCAD deficiency.