Objective: To evaluate the association between cognitive decline and quality of life in hypertensive elderly persons. Methods: A quantitative, cross-sectional, analytical study involving 125 hypertensive elderly individuals of both genders attending the HIPERDIA Program in São Luís, in the state of Maranhao, was performed. The Mini Mental State Exam (MMSE) was used to evaluate cognitive decline and quality of life was assessed using the Medical Outcomes Study 36 Short-Form Health Survey (SF-36). The normality of the data was verified by the Shapiro-Wilk test. The Mann-Whitney test was also applied (quality of life). The association between cognitive decline and quality of life was evaluated using Spearman's coefficient. Results: The prevalence of cognitive decline was 20.8% and there was a predominance of elderly persons with a low educational level (45.83%). Hypertensive elderly individuals with cognitive decline had a poorer quality of life than those without cognitive decline. A positive association between cognitive function and quality of life was observed for the following domains: functional capacity (r=0.222; p=0.01), pain (r=0.1871; p=0.04), and emotional aspects (r=0.3136; p=0.0005). Conclusion: The results of this study suggest that cognitive decline directly affects the quality of life of the elderly by limiting the capacity to perform activities of daily living, especially if associated with painful medical conditions and emotional disturbances.