The question addressed in this review is whether supplementation with thyroid hormones during the perioperative period improves the outcome of patients undergoing coronary artery bypass surgery. Altogether 88 relevant papers were identified using the below mentioned search, seven papers represented the best evidence to answer the question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses were tabulated. We conclude that although widespread interest has been shown on the use of thyroid hormones in the perioperative period, and the effect of cardiopulmonary bypass on thyroid hormone metabolism widely studied, there is no substantial evidence to justify routine use of thyroid hormones in patients undergoing coronary artery bypass grafting.