Purpose: Although perioperative antibiotic prophylaxis is used to prevent surgical site infection (SSI), thyroid surgery is classified as a clean surgical procedure and routine use of perioperative antibiotic prophylaxis is not recommend. The purpose of this study is to evaluate the therapeutic benefits of using perioperative antibiotic prophylaxis in thyroid surgery. Methods: We evaluated medical records of 1,895 patients who underwent thyroid surgery between January 2013 and December 2013. We divided 2 groups with or without perioperative antibiotic prophylaxis. Clinical factors including sex, age, body mass index (BMI), and comorbidity and surgical factors for SSI were analyzed. Results: The male to female ratio was 1:3.3, the average age was 43 (14-82) years old. The numbers of groups without and with antibiotic prophylaxis were 593 and 1,303. Thirty-seven cases (2.0%) of postoperative complications were observed including chyle leakage, SSI, and nerve injury. The SSI was occurred in 10 patients (0.5%). Clinical factors with SSI were analyzed and there was no statistical significance between 2 groups. Conclusion: In thyroid surgery, perioperative antibiotic prophylaxis may not be required routinely once the surgical procedure underwent with aseptic condition and the patients care was performed appropriately.