Background and Objectives: Autoimmune thyroiditis (AIT) is a form of thyroiditis associated with autoimmune antibodies. Few studies have measured thyroid volume in Asians. This study was undertaken to determine the distribution of thyroid volume and to explore possible correlations between thyroid volume and other factors in a Korean cohort. Materials and Methods: Two hundred eleven patients who underwent 99m Tc-pertechnetate thyroid scintigraphy between 2009 and 2011 were recruited and their thyroid volume was measured. AIT was defined as having thyroperoxidase antibody (TPOAb) and/or thyroglobulin antibody (TgAb) positivity and TRAb negativity, regardless of thyroid function. Results: The mean thyroid volume was 32.1 mL in AIT patients. The distribution of thyroid volume was normal after log transformation. Thyroid volume was larger in patients with both autoantibodies than in patients with only one antibody (p＜0.001). The first quartile of patients grouped according to thyroid volume were older (52.1 years, p=0.037) than the patients in other quartile groups. Thyroid volume correlated independently with TPOAb titer, and TgAb titer adjusted for other factors in a multivariate analysis. Conclusion: Thyroid volume in Korean AIT patients had an unimodal distribution and correlated with autoantibody titer.