['Increased T wave alternans (TWA) represents ventricular depolarization heterogeneity and is a non-invasive marker of sudden cardiac death. This study sought to determine whether myocardial structural alteration and dysfunction in patients with type 2 diabetes mellitus (T2DM) is associated with an increased TWA.', 'We recruited 108 T2DM patients (59.2±9.7 years and 52% male) without prior history of cardiovascular disease and normal treadmill stress testing. TWA was analyzed during treadmill testing in all standard precordial leads by time-domain method. Transthoracic echocardiography was performed to measure myocardial structural alteration by calibrated integrated backscatter (IBS), left ventricular (LV) systolic function by conventional method, and speckle tracking-derived global longitudinal strain (GLS), and LV diastolic function.', 'A total of 29 (26.9%) patients had a high TWA of ≥47mV (defined by ≥75 percentile of the study population). Patients with and without elevated TWA had a similar LV dimension and ejection fraction. Nonetheless, patients with high TWA had a higher calibrated IBS (-15.8±4.0dB vs. -17.9±5.3dB, p=0.04), more impaired GLS (-18.4±2.0% vs. -19.3±1.4%, p=0.02), and a higher prevalence of diastolic dysfunction (60 vs. 33%, p=0.02). Multivariable analysis demonstrated that high TWA was independently associated with calibrated IBS, GLS, and LV diastolic dysfunction grading.'] Is increased T-wave alternans associated with subclinical myocardial structural and functional abnormalities in patients with type 2 diabetes?