Interleukin 2 (IL-2), a Th1 lymphocyte-derived cytokine, is thought to play an important role in the pathogenesis of type 2 diabetes and rheumatoid arthritis (RA). The aim of our study was to evaluate changes in serum IL-2 levels and their correlation with glucose metabolism abnormalities, such as insulin resistance, in patients with RA. Thirty-six subjects with varying degrees of disease activity and 20 healthy age-, sex- and body mass index-matched control individuals were evaluated. Patients with any causes of peripheral insulin resistance were excluded. After a 12-h overnight fast, fasting insulin levels, homeostatic model assessment-insulin resistance (HOMA-IR) estimated insulin sensitivity, and serum IL-2 levels were significantly higher in all patients with RA; than in the control individuals. Fasting insulin, HOMA-IR scores and IL-2 levels were correlated in the RA group. This study showed that patients with RA have altered IL-2 regulation, and that there was a significant correlation between serum IL-2 levels and insulin sensitivity.