Background: Alpha 2-adrenergic agonists decrease sympathetic tone with ensuing attenuation of neuroendocrine and hemodynamic responses to anesthesia and surgery. Also, administration of beta -adrenergic antagonists contributes to prophylaxis against hypertension, tachycardia and myocardial ischemia and myocardial protection during cardiac surgery. The effects of dexmedetomidine (DEX), a highly specific alpha -adrenergic agonist, on these responses have not yet been fully reported in patients undergoing cardiac surgery. Esmolol (ESM) is a cardioselective, short-acting - blocking agent. Previous studies have established the effectiveness of esmolol in the reduction of hemodynamic responses during anesthetic induction. Aim: The study of hemodynamic responses of dexmedetomidine and esmolol and their effects on the anesthetic requirements during anesthesia in beating heart surgery.  Conclusion: Dexmedetomidine in patients undergoing beating heart surgery decreased intraoperative sympathetic tone, induced sedation, attenuated hyperdynamic responses to anesthesia and surgery and overall hemodynamic variability than esmolol. The need for anesthetics, muscle rigidity, perioperative myocardial ischemia and shivering were less also in DEX group.