BACKGROUND: This cross-sectional study was designed to examine the association between home blood pressure and cognitive impairment in elderly patients with type 2 diabetes. METHODS: Home blood pressure was measured in the morning and evening for 14 consecutive days in 749 patients with type 2 diabetes. A total of 231 patients were included in the study population. Cognitive function was evaluated using the Mini-Cog test, which is used as a screening for cognitive impairment in elderly patients. We performed a logistic regression analysis and measured the area under the receiver operating characteristic curve and estimated home blood pressure as a marker of cognitive impairment. RESULTS: The adjusted odds ratio (95% confidence interval) of evening systolic blood pressure for cognitive impairment was 1.24 (1.02-1.53). Evening systolic blood pressure showed the highest area under the receiver operating characteristic curve for cognitive impairment in both unadjusted and adjusted models. In all subgroup analyses except gender, home blood pressure showed higher area under the receiver operating characteristic curve than clinic blood pressure. CONCLUSION: Home blood pressure was associated with cognitive impairment in elderly patients with type 2 diabetes.