Abstract: AIM: To investigate the relationship between hypertension and cognitive function impairment in the very elderly. METHODS: General conditions and health status were surveyed in 210 individuals with hypertension and 140 controls. Patients’ cognitive function was assessed by the mini-mental state examination (MMSE) and other relative data were collected. RESULTS: The scores of total MMSE, orientation and visuospatial perception in hypertensive subjects were lower than those in non-hypertensive subjects (P<0.05). MMSE score decreased with the increasing duration of hypertension. MMSE scores in patients with hypertension ≥40 years were significantly lower than those in patients with hypertension who were no more than 40 years (P<0.01). MMSE scores of patients who achieved target blood pressure were significantly higher than those who failed to achieve target blood pressure (P<0.05). Logistic regression analysis in groups with different blood pressure level revealed that high diastolic pressure (≥160 mmHg) and high pulse pressure (≥60 mmHg) were independent risk factors for the impairment of cognitive function in the very elderly. CONCLUSION: Cognitive function impairment in the very elderly is closely associated with high diastolic pressure, high pulse pressure, longer duration of hypertension and failure to achieving target blood pressure. Prevention and control of hypertension may be helpful in slowing down impairment of cognitive function in very elderly subjects.