This study aimed to investigate the relationship between carotid atherosclerosis and left ventricular hypertrophy on electrocardiogram (ECG-LVH) on adults living in the community. A total of 9,266 adults who participated in the Namwon Study were included in this analysis. Carotid atherosclerosis, including intima-media thickness (IMT) and plaques, were assessed using high-resolution B-mode ultrasound. ECG-LVH was determined using the Sokolow-Lyon voltage (SokV) and Cornell voltage (CorV) criteria. The prevalence of ECG-LVH was 12.7% using the SokV criteria and 9.7% using the CorV criteria. After full adjustment, compared to the lowest quartile of common carotid artery IMT (CCA-IMT), the odds ratios and 95% confidence intervals for ECG-LVH of the carotid IMT quartiles 2, 3, and 4 increased linearly as follows: 1.54 (1.24-1.90), 1.62 (1.31-2.02), and 1.91 (1.54-2.38), respectively, for the SokV criteria (p<0.001); and 1.33 (1.05-1.68), 1.41 (1.11-1.78), and 1.48 (1.16-1.88), respectively, for the CorV criteria (p=0.003). Positive associations between the carotid bulb IMT (CB-IMT) quartiles and the ECG-LVH were also observed, although the magnitudes of association between CB-IMT and ECG-LVH were slightly lower than those of CCA-IMT. However, no significant association between carotid plaques and ECG-LVH as defined by the SokV or CorV criteria was found. The present study demonstrated that increased carotid IMT, but not carotid plaques, is significantly associated with LVH defined by various ECG criteria in a large population.