© 2019 Elsevier Inc. Background: The American Thyroid Association (ATA) issued specific preoperative preparatory guidelines for patients undergoing thyroidectomy for treatment of Graves' disease. Our goal is to determine if compliance with these guidelines is associated with better outcomes. Methods: A retrospective review of a prospectively maintained database identified 228 patients with Graves' disease who underwent total thyroidectomy between August 2007 and May 2015. Patients treated in compliance with ATA guidelines were compared with those not in full compliance with the current preparatory guidelines. Results: At the time of surgery, 52% of all patients followed ATA guidelines. Patients who were prepped per ATA guidelines had fewer episodes of intraoperative tachycardia (0.3 versus 4.5, P = 0.04) but had no difference in peak systolic blood pressure or in number of episodes of systolic blood pressure > 180 mmHg. ATA prepped and nonprepped patients had similar mean operating room time and length of stay. ATA prepped and nonprepped patients had similar complication rates, including transient hypocalcemia (30.4% versus 25.5%, P = 0.45), prolonged hypoparathyroidism (0.98% versus 4.3%, P = 0.15), hoarse voice (10.8% versus 7.5%, P = 0.42), permanent recurrent laryngeal nerve paralysis (2.9% versus 2.1%, P = 0.71), and hematoma (2.9% versus 0%, P = 0.09). Conclusions: Our data suggest that compliance with ATA guidelines for thyroidectomy preparation is not essential for a successful surgical outcome. Although preparation per the guidelines decreased the frequency of intraoperative tachycardia, it did not impact intraoperative hypertension, operating room time, or postoperative complications.