Background: Prolonged hypertension is believed to affect brain structure due to chronic vascular stress. Objective: To assess the correlation between hypertension duration and changes in brain volumes using 3D MRI. Methods: This cross-sectional study involved 100 hypertensive individuals aged 30–60 years. Brain volumes (gray and white matter) were measured using 3D MRI. Pearson correlation analysis was used to evaluate associations with hypertension duration. Results: Strong negative correlations were found between hypertension duration and both gray and white matter volumes (r = -0.49 to -0.56, p < 0.001). Conclusion: Longer duration of hypertension is associated with reduced brain volume, reinforcing the need for early detection and sustained management of blood pressure.