Objective: To evaluate the relationship between left ventricular hypertrophy (LVH) and geometrical structure of the left ventricle with the risk of arrhythmia and QT dispersion (QTd) in hypertensive patients. Methods: Eighty patients were included (mean age 53 ± 11 years, 45 women,) in the study. Among them, concentric LVH was present in 30, concentric remodelling in 15 and normal left ventricular geometry in 35 patients. Twenty-four hours electrocardiographic monitoring and QTd calculation were performed for all patients. Results: Lown grade 2-3 ventricular arrhythmia was found in 30 patients (%37) and Lown grade 4a–4b ventricular arrhythmia was documented in 17 patients (%21). The frequency of > Lown 2 ventricular arrhythmia in patients with concentric LVH was significantly higher than those of the subjects with concentric remodelling or normal geometry (p <0.01). The percentage of > Lown 2 ventricular arrhythmias were %80 in patients with LVH and %10 in patients wihout LVH. QT and QTc dispersions in patients with concentric hypertrophy were significantly longer than those of the patients with concentric remodelling and normal geometry. Additionally, QT and QTc dispersions in patients with ventricular arrhythmias were more frequent than in those without (p<0.001). The left ventricular mass index correlated positively both with the QTd and the QTc dispersions (r=0.33, p=0.007, r=0.26, p= 0.03, respectively). The left ventricular mass index also correlated significantly with both grades (Lown 2-3 and Lown 4a-4b) of ventricular arrhythmia (r=0.59, p=0.001; r= 0.53, p=0.001, respectively). Conclusion: In hypertensive patients, especially in those with concentric LVH, the incidence of ventricular arrhythmia increases in relation with QT dispersion.