New-onset diabetes after transplantation (NODAT) is a known serious long-term complication of renal transplantation. A number of risk factors for development of NODAT have been established. Age, body mass index (BMI), ethnicity, hepatitis C infection, and immuno-suppressive therapy are among the most important. Chronic inflammation now is supposed to play a pivotal role in the pathogenesis of type 2 diabetes. Studies suggest a contributory role for low grade activation of the immune system in the development of type 2 diabetes, and both C-reactive protein (CRP) and IL-6 levels have been identified as risk factors for the future development of type 2 diabetes. Moreover, despite some controversial data, IL-6 gene promoter polymorphism at position -174 (G/C), which is associated with different transcription rates, seems to predict type 2 diabetes. Some researchers previously reported no association between diabetes and IL-6 gene promoter polymorphism at position -174 (G/C) in long-term renal transplant recipients (RTR). Nevertheless, the relevance of this study is seriously hampered by selection bias, lack of definition of diabetes, and confusion between type 2 diabetes and NODAT.In this study, we want to find the association between IL-6 gene promoter polymorphism at position -174 and the development of NODAT.