Abnormal left ventricle (LV) geometric patterns are associated with an increased risk of vascular complications of hypertension (HT). The association between red-cell distribution width (RDW) and HT has been recently investigated; however, the relationship between abnormal LV geometric patterns and RDW has not been studied before. The aim of this study was to investigate the relationship between RDW and abnormal LV geometric patterns in patients with untreated essential HT. Measurements were obtained from 139 patients with untreated essential HT (mean age=51.3±16.3 years). Four different geometric patterns (NG, normal geometry; CR, concentric remodeling; EH, eccentric hypertrophy; CH, concentric hypertrophy) were determined according to the LV mass index (LVMI) and relative wall thickness (RWT). RDW, lipid parameters and other biochemical markers were measured in all patients. While the highest RDW values were detected in the CH group (P<0.05, for all), it was similar among the NG, CR and EH groups (P>0.05, for all). RDW was associated with age, LVMI and LV geometry in bivariate analysis (P<0.05, for all). In a receiver operating characteristic (ROC) curve analysis, a level of RDW>14.5 predicted CH with 81% sensitivity and 59% specificity. Age (beta=0.309, P=0.001), LV geometry type (beta=0.228, P=0.01) and RWT (beta=-0.278; P=0.25) were independent predictors of high RDW in multiple linear regression analysis. In conclusion, the highest RDW values were observed in the CH group in the untreated essential HT patients. RDW seems to be a useful tool for the prediction of end-organ damage in patients with untreated essential HT.