Background: Successful prevention of aortic complications has resulted in improved survival of Marfan syndrome (MFS). With increasing age, however, ventricular arrhythmia and heart failure are emerging as life-threatening manifestations of myocardial dysfunction. We aimed to investigate preclinical myocardial dysfunction and changes in myocardial mechanics in patients with MFS using 2-dimensional strain imaging. Methods: From July 2008 to March 2010, we enrolled patients with MFS who fulfilled the Ghent criteria. Patients who underwent cardiovascular surgery or have valvular heart disease of moderate grade or more severity were excluded. Finally, we studied 25 patients with MFS (8 men and 17 women; average age: 33.5 짹 15.3 years). These patients was compared with age and sex matched normal control group (n=20). We analyzed results of 2D echocardiography including tissue Doppler imaging and 2D velocity vector imaging. Results: Patients with MFS had lower early septal diastolic velocity (e��� ;0.11 짹 0.004 vs 0.13 짹 0.006 m/sec, p=0.023). On 2D strain analysis, patients with MFS had lower global circumferential strain (-23 짹 4 vs -25 짹 4 %, p=0.022) but similar global longitudinal strain (-18 짹 3 vs -18 짹 3 %) compared with control subjects. Biplanar strain vector magnitude was similar (29 짹 4 vs 31 짹 4) in both groups, but was more longitudinally oriented in patients with MFS (38 짹 7 vs 35 짹 5 degrees, p=0.085). Conclusion: Patients with MFS have significantly lower circumferential myocardial strain. Although statistically insignificant, there is tendency of more longitudinal orientation of myocardial strain in MFS. These findings provide insights into pathophysiology of primary myocardial dysfunction of MFS.