Background: Hypertension is a common condition and leading cause of cardiovascular disease. We previously reported results of a cluster-randomized trial evaluating a home blood pressure (BP) telemonitoring and pharmacist management intervention, with significant reductions in systolic BP (SBP) favoring the intervention arm found over 6, 12, and 18 months and in diastolic BP (DBP) found over 6 and 12 months. This analysis examined the durability of the intervention effect on BP through 54 months of follow-up. Methods: The Hyperlink trial randomized 16 primary care clinics having 450 study-enrolled patients with uncontrolled hypertension to either Telemonitoring Intervention (TI) or usual care (UC) study arms. BP was measured as the mean of 3 measurements obtained at each research clinic visit. General linear mixed models utilizing a direct likelihood-based ignorable approach for missing data were used to examine change from baseline to 54 months in SBP and DBP. Results: BP measurements were obtained from 164 (74%) in UC and 162 (71%) of TI patients at the 54 month follow-up visit. For TI patients, baseline SBP was 148.2 mm Hg and 54 month follow-up was 131.2 mm Hg (-17.0 mm Hg, p<.001). For UC patients, baseline SBP was 147.7 mm Hg and 54 month follow-up was 131.7 mm Hg ( - 16.0 mm Hg, p<.001). The differential reduction by study arm in SBP from baseline to 54 months was -1.0 (95% CI: -5.4 to 3.4, p=0.63). For TI patients, baseline DBP was 84.4 mm Hg and 54 month followup was 77.8 (-6.6 mm Hg, p<.001). For UC patients, baseline DBP was 85.1 mm Hg and 54 month follow-up was 79.1 mm Hg (-6.0 mm Hg, p<.001). The differential reduction by study arm in DBP from baseline to 54 months was -0.6 mm Hg (95% CI: -3.5 to 2.4, p=0.67). Conclusion: Significant BP reductions in the TI arm relative to UC were no longer seen at 54 month follow-up. More work is needed to ascertain the optimal duration and reinforcement that could be used to maintain intervention benefits over a longer period of time.