Background: The differentiation between ischemic and nonischemic cardiomyopathy is clinically important because of different management and prognosis. Echocardiography is most useful noninvasive modality for diagnosis of dilated cardiomyopathy (DCM). However, conventional echocardiography has limited value for differentiating causes of DCM. We hypothesized that two-dimensional speckle tracking could help distinguishing ischemic from nonischemic DCM. Methods: Forty-four patients were consecutively enrolled. Each twenty-two patients were included in ischemic and nonischemic DCM groups (66 짹 9 years vs. 64 짹 15 years, p=0.494). We enrolled the patients with decreased ejection fraction (<50%) with dilated left ventricular (LV) end-diastolic dimension. Patients with atrial fibrillation or significant valvular disease were excluded. We achieved peak systolic radial and circumferential strain in short axis images and peak systolic longitudinal strain in apical images. We analyzed standard deviation (SD) of the peak systolic strain and maximal difference (maximal - minimal value) of the strain values of 18 segments in ischemic and nonischemic DCM groups. Results: Ejection fraction and LV end-diastolic volume were not different in two groups (Ejection fraction, 37.4짹8.1% vs. 34.4짹9.6%, p=0.280; LV end-diastolic volume, 149.0짹31.8 ml vs. 162.6짹52.4 ml, p=0.439). The SD of peak systolic circumferential and longitudinal strain of ischemic DCM were significantly higher than that of nonischemic (7.9짹2.3 vs. 5.6짹1.5 p<0.001 and 6.8짹1.9 vs. 4.9짹1.3 P<0.001). Maximal difference of peak systolic circumferential and longitudinal strain of ischemic DCM were greater than that of nonischemic DCM (-29.4짹9.1 vs. -20.4짹6.2, p<0.001 and -25.4짹7.3 vs. -19.1짹6.3, p<0.001). However, parameters using peak systolic radial strain were not different in two groups. The SD of peak systolic longitudinal strain had the highest area under the curve (AUC=0.833) in ROC analysis. A cut-off value 5.8 of SD of peak systolic longitudinal strain predicted ischemic DCM with 81.0% sensitivity, 78.3% specificity, 77.3% positive predictive value and 81.8% negative predictive value. Conclusions: The measure of SD and maximal difference of peak systolic circumferential and longitudinal strain were useful for differentiation between ischemic and nonischemic DCM. The analysis of two-dimensional speckle tacking could provide more information for clinical approach in DCM patient.