It has been suggested that copper ion is involved in the pathogenesis of various diseases. The aim of this study is to examine the association of serum copper levels and glycemic control in patients with type 2 diabetes. We recruited a total of 132 patients with type 2 diabetes, and measured their serum copper levels by atomic absorption spectrometry. Serum copper levels were positively correlated with HbA1c levels (r=0.176, p=0 .044). In addition, after 3-month glycemic control, we evaluated whether the improvement of glycemic control influenced serum copper levels. As hemoglobin A1c (HbA1c) levels were decreased (from 8.7% to 6.8%, p<0.001), copper levels tended to be decreased (from 105.7 μg/dL to 101.8 μg/dL, p=0.069). In conclusion, it is likely that serum copper levels are associated with glycemic control in patients with type 2 diabetes.