BACKGROUND: Anemia is associated with worse long term outcomes in heart failure. However, there is little evidence on the effect of low hemoglobin level to the left ventricular (LV) structure and diastolic function in hypertensive patients. This study assessed the relationship of hemoglobin level to LV filling pressure in elderly hypertensive patients. METHODS: From January 2005 to January 2009, 200 newly diagnosed hypertensive patients over 50 years old (mean age 60 +/- 6 years, 116 women) were analyzed. The clinical parameters and comprehensive echocardiographic data were obtained. The patients with and without anemia were compared. RESULTS: There were significant differences between the anemic and non-anemic groups in the LV mass index (115.27 +/- 34.95 vs. 103.75 +/- 28.21 g/m2), left atrial (LA) volume index (29.31 +/- 10.74 vs. 24.99 +/- 7.43 mL/m2), and E/E' (11.92 +/- 4.34 vs. 9.37 +/- 2.51). Chronic renal failure was more prevalent in anemic group. On multivariate logistic analysis, anemia was significantly correlated with high LV filling pressure, reflected by E/E', even after controlling for LV mass index and LA volume index. Furthermore, E/E' was significantly correlated with the hemoglobin level (R2 = 0.093, p < 0.001). CONCLUSION: In newly-diagnosed hypertensive patients over 50 years old, the presence of anemia was significantly associated with elevated LV filling pressure and LV structural changes. And the hemoglobin level was negatively correlated with noninvasively estimated LV filling pressure.