Background and Objectives:The aim of this study was to evaluate the myocardial function in patients with nonhypertensive, nondiabetic metabolic syndrome (MS) Subjects and Methods: We selected asymptomatic MS patients (n=42) without evidence of hypertension or diabetes, and compared with age-matched normal healthy individuals (n=20). All patients were analyzed by conventional Doppler, tissue Doppler (TD) myocardial velocity, and strain imaging. Strain and strain rate (SR) were measured at 8 segments in apical 2 and 4 chamber views by TD imaging, and the average was used for analysis. Results: There were no significant differences in E, A, E/A ratio, and DT as well as in LVEF, wall thickness and LV mass index between two groups. However, systolic and early diastolic TD velocities were significantly lower in MS patients than in control groups (2.8 짹 1.1 vs. 4.0 짹 1.5 cm/s, 4.0 짹 1.9 vs. 5.0 짹 1.9 cm/s, p<0.001, p<0.001, respectively). In addition, systolic and early diastolic SR, and peak systolic strain were significantly lower in nonhypertensive, nondiabetic MS patients than in normal healthy individuals (1.1 짹 1.0 vs. 1.3 짹 0.6 s-1, 1.3 짹 0.7 vs. 1.4 짹 0.7 s-1, 16.9 짹 8.9 vs. 20.5 짹 7.6%, p=0.028, p=0.035, p<0.001, respectively). Conclusion: These results indicate that metabolic syndrome patients without hypertension or diabetes may have myocardial dysfunction by TD imaging, even if they appear to have normal findings on 2D and conventional Doppler studies.