Objective: to verify the influence of cognitive impairment on adherence to antihypertensive treatment in the aged. Method: systematic review, with the inclusion of original articles, available in full, in Portuguese, English and Spanish, published between the years 2007 and 2021. The search was made in SCIELO, PUBMED, LILACS and MEDLINE, with the following descriptors: “Cognitive Dysfunction”; “Medication Adherence”; “Hypertension”; “Aged”. Results: of the 216 studies found, five were selected. Four showed a negative relationship between cognitive impairment and adherence of the aged to antihypertensive treatment. It was evidenced that aged with cognitive impairment were more likely to have inadequate blood pressure control. Conclusion: it is observed that cognitive impairment is an important risk factor for poor adherence to treatment in hypertensive aged. Early detection becomes essential, aiming to adapt care to the cognitive conditions of the aged and optimize medication management to achieve adequate control of blood pressure levels.