Background: Epidemiological studies have reported positive, negative, U-shaped or J-shaped association between high blood pressure and cognitive function as well as dementia whereas other studies have not reported any significant association. The aim of this study was to examine the association between hypertension and cognitive impairment in the elderly residents of Kahrizak Charity Foundation (KCF). Methods: This cross sectional study was done in Kahrizak Charity Foundation in suburban areas of Tehran, Iran during 2008. The data were collected over one week. Among the 850 elderly residents of the Foundation who were ≥ 65 years old, 185 individuals were chosen randomly. The Mini-Mental State Examination (MMSE) was completed for all. Mean of all blood pressure readings were recorded while anthropometric and biochemical measurements were performed. Results: The findings indicated that in participants with cognitive impairment, systolic blood pressure, diastolic and mean blood pressures were higher than people with normal cognitive function but the differences were not significant statistically. The odds ratio of cognitive impairment in patients with and without hypertension was 1.52 and 1.58, respectively (P>0.05). Conclusion: This study did not show any significant association between hypertension and cognitive impairment in the elderly residents of Kahrizak Charity Foundation.