Background: The aim of the present study was to evaluate left ventricle (LV) systolic and diastolic function, using tissue Doppler echocardiography (TDE) and color M-mode flow propagation velocity, in relation to blood glucose status in normotensive patients with type 2 diabetes mellitus (T2DM) who had no clinical evidence of heart disease. Methods: Seventy-two patients with T2DM (mean age 49.1 +/- 9.8 years) without symptoms, signs or history of heart disease and hypertension, and 50 ages matched healthy controls (mean age 46.1 +/- 9.8 years) had echocardiography. Systolic and diastolic LV functions were detected by using conventional echocardiography, TDE and mitral color M-mode flow propagation velocity (V-E). Fasting blood glucose level (FBG) after 8 hours since eating a meal, postprandial blood glucose level (PPG), and HbA(1C) level were determined. The association of FBG, PPG and HbA(1C) with the echocardiographic parameters was investigated. Results: It was detected that although systolic functions of two groups were similar, diastolic functions were significantly impaired in diabetics. No relation of FBG and PPG with systolic and diastolic functions was determined. However, HbA(1C) was found to be related to diastolic parameters such as E/A, Em/Am, V-E and E/V-E (beta = -0.314, P = < 0.05; beta = -0.230, P < 0.05; beta = -0.602, P < 0.001, beta = 0.387, P < 0.005, respectively). In addition to HbA(1C), LV, diastolic functions were also correlated with age and diabetes duration. Conclusion: Diastolic LV dysfunction may develop even in absence of ischemia, hypertension, and LVH in T2DM. FBG and PPG have no effect on LV functions, but HbA(1C) levels may affect diastolic parameters.