Abstract: AIM:To explore whether red cell distribution width (RDW) values differ between a healthy population and patients with pre-hypertension or hypertension who are otherwise healthy. METHODS: Eighty patients with hypertension, 82 patients with pre-hypertension and 85 healthy controls participated in the study. Data from the three groups including gender, age, blood pressure, red blood cell distribution width and blood biochemistry were statistically analyzed. RESULTS: RDW values were (13.0±1.0)%, (15.0±0.8)% and (16.9±0.8)%, respectively, in control group, pre-hypertension group and hypertension group (P<0.05). RDW was higher in pre-hypertension group and hypertension group compared with that in healthy controls, independent of smoking habit, inflammatory status, anemia and renal function. CONCLUSION: Systolic and diastolic blood pressures are strongly correlated with red cell distribution width.