Objectives. To examine the relation between left ventricular (LV) diastolic function and gamma-glutamyltransferase (GGT) in diabetic individuals with or without previously diagnosed cardiovascular disease. Design. A cross-sectional population-based study. Setting. A university hospital. Subjects. A total of 205 diabetic patients were included in the study. Patients who had cardiovascular disease constituted the study group (CD group; n = 112) and patients who had no complications constituted the control group (ND group; n = 93). Left ventricular diastolic function was assessed by pulsed Doppler tissue imaging and was determined by ratio E wave/A wave. Main outcome measures. GGT levels were higher in CD Group than ND Group (25.9 +/- 2.1 vs. 20.1 +/- 1.5 units/L, p = 0.023). Significant difference between mean diastolic function parameters, such as E wave/A wave (0.86 +/- 0.27 vs. 1.01 +/- 0.36, p = 0.015), of the diabetic patients with and without cardiovascular disease was present. In this study, E wave/A wave correlated with age, waist-to-hip ratio (WHR), systolic blood pressure, and total cholesterol. Negative correlations were also found between LV diastolic function and GGT (beta = -0.009, p = 0.008). Conclusion. The data showed that in type 2 diabetic patients, with evident cardiac disease, metabolic parameters affect diastolic functions more than systolic functions. Besides known cardiovascular disease risk factors, GGT might be an additional marker of diastolic dysfunction in diabetes patients with cardiovascular disease.</.