BACKGROUND: Hypertension is still a health problem both in developed and developing countries. Hypertension can cause various complications; one of them is cognitive function impairment. AIM: This study aimed to look at the relationship of hypertension with cognitive function. This research can also be useful to help optimise the health of the elderly, maximise quality of life and avoid hypertension as a risk factor for cognitive impairment in the elderly at the Karya Kasih Nursing Homes, Medan from May to June 2018. METHODS: This research was carried out by analytic observational with cross-sectional research approach. In this study, 57 elderly from Karya Kasih Nursing Homes Medan who met the inclusion and exclusion criteria participated. Assessment of cognitive function used Mini-Mental State Examination (MMSE), Six Item Cognitive Impairment Test (6CIT) and Abbreviated Mental Test Score (AMT) instruments. RESULT: This study obtained a significant relationship between the history of hypertension with impaired cognitive function (p = 0.003). The results of the cognitive function examination with MMSE showed that among 57 elderly, 16 people (43.2%) were normal and 21 people (56.8%) had impaired cognitive function in the first degree hypertension group, besides that, 3 people were normal (15%) and 7 people (85%) had impaired cognitive function in the second degree hypertension group (p = 0.031). Based on the result of mild and severe cognitive function impairment, among 12 people (57.1%) and 9 people (42.9%) had a mild and severe cognitive function impairment, respectively, in first-degree hypertension. 3 people (17.6%) and 14 people (82.4%) had a mild and severe cognitive function impairment, respectively, in the second-degree hypertension (p = 0.013). The 6-CIT instrument also showed a significant relationship between the severity of hypertension and impaired cognitive function (p = 0.027), and there was no significant relationship with AMT instruments (p = 0.078). CONCLUSION: There was a relationship between the history or duration and degree of hypertension with cognitive dysfunction in the elderly at the Karya Kasih Nursing Home Medan.