Rationale:Thyroid storm is a rare and life-threatening metabolic crisis because of an emergent release of excess thyroid hormone. Sinus tachycardia induced by excess thyroid hormone may result in congestive heart failure due to decreased diastolic filling time.Patient concerns:A controlled hyperthyroidism patient with severe sinus tachycardia.Diagnoses:A controlled hyperthyroidism patient was induced thyroid storm during huge pelvic mass resection.Interventions:Application of low-dose neostigmine and -antagonist esmolol to control the heart rate (HR) avoided hemodynamic collapse.Outcomes:The patient improved dramatically following application of low-dose neostigmine instead of esmolol to control the HR avoided hemodynamic collapse.Lessons:Our case suggests that neostigmine, an acetylcholinesterase inhibitor, may warrant further investigation in patients with thyroid storm-induced severe sinus tachycardia.