Background: Diabetes is thoroughly evidenced to increase the risk of development of heart failure. Cardiac adverse effects influenced by diabetes have been demonstrated for the left ventricle function. Hence, the purpose of the present study was to investigate whether diabetes has any effect on the right ventricular function. Methods: Standard and tissue Doppler echocardiography was performed on fifty asymptomatic diabetic patients and fifteen healthy volunteers. We assessed the right ventricular function by measuring the right ventricular Sm, Em, Am, E-A m and IVRTm. Results: No statistically significant differences were found among all groups regarding age, gender, BMI, smoking and duration of diabetes. The right ventricular function was impaired in the diabetic group, indicated by significantly lower values of peak early diastolic velocity Em (13.3 ± 2.31 in patients vs. 16.4 ± 1.9 among the control group) with p-value (.000) and prolonged right ventricular Isovolumic relaxation time IVRTm (35.5 ± 7.57 in patients vs. 24.9 ± 5.07 among the control group) with p-value (.000). Where we found that the Em –Am were at borderline of level of significant (0.05) (1.18 ± .15 in patients vs. 1.27 ± .12 among the control group). Conclusions: Diabetes Mellitus affects right ventricular diastolic function in the presence of normal right ventricular systolic function. Impairment was evident mainly by TDI- derived indexes.