OBJECTIVES: The aim of our study was to evaluate the total atrial conduction time and its relationship to subclinical atherosclerosis, inflammation and echocardiographic parameters in patients with type 2 diabetes mellitus. METHODS: A total of 132 patients with type 2 diabetes mellitus (mean age 54.5±9.6 years; 57.6% male) and 80 age- and gender-matched controls were evaluated. The total atrial conduction time was measured by tissue-Doppler imaging and the carotid intima-media thickness was measured by B-mode ultrasonography. RESULTS: The total atrial conduction time was significantly longer in the patients with type 2 diabetes mellitus than in the control group (131.7±23.6 vs. 113.1±21.3, p<0.001). The patients with type 2 diabetes mellitus had significantly increased carotid intima-media thicknesses, neutrophil to lymphocyte ratios and high-sensitivity C-reactive protein levels than those of the controls. The total atrial conduction time was positively correlated with the high-sensitivity C-reactive protein level, neutrophil to lymphocyte ratio, carotid intima-media thickness and left atrial volume index and negatively correlated with the early diastolic velocity (Em), Em/late diastolic velocity (Am) ratio and global peak left atrial longitudinal strain. A multiple logistic regression analysis demonstrated that the neutrophil to lymphocyte ratio, carotid intima-media thickness and global peak left atrial longitudinal strain were independent predictors of the total atrial conduction time. CONCLUSIONS: We suggest that subclinical atherosclerosis and inflammation may represent a mechanism related to prolonged total atrial conduction time and that prolonged total atrial conduction time and impaired left atrial myocardial deformation may be represent early subclinical cardiac involvement in patients with type 2 diabetes mellitus.