OBJECTIVES: The Take Control of Your Blood Pressure trial randomized 636 community-dwelling individuals with hypertension to evaluate the impact of a telephonic behavioral self-management intervention, home blood pressure monitoring, and both interventions combined compared to usual care on reducing systolic blood pressure (SBP) over 24 months. At 24 months, the combined intervention demonstrated a significant 3.9 mmHg (95%CI: 0.9,6.9) reduction in SBP relative to usual care. Patients randomized to home BP monitoring or the behavioral intervention had less improvement (0.6 mmHg and -0.6 mmHg, respectively). A prospective economic evaluation was performed. METHODS: Measures of medical resource use costs were derived from electronic data representing medical care delivered within the Duke University Health System. Intervention-related costs, including patient time, were estimated using patient-level data collected during the trial, administrative records, and published unit costs. Sensitivity analyses were conducted to evaluate the impact of changing assumptions about overhead costs and time between completed phone encounters when estimating costs associated with the behavioral intervention. RESULTS: On average, over 24 months, patients incurred $6,965 (SD=22,054) in inpatient costs and $8,676 (SD=9,368) in outpatient costs, with no significant differences across intervention groups. When applying base-case assumptions, 24-month intervention costs were estimated to be $90 (SD=2) for home blood pressure monitoring, $345 (SD=64) for the behavioral intervention ($31 per phone encounter) and $416 (SD=93) for the combined intervention. In sensitivity analyses, the cost for each phone encounter ranged from approximately $10 to $45. Patient time costs were estimated at $585 (SD=487) for home monitoring, $55 (SD=16) for the behavioral intervention and $741 (SD=529) for the combined intervention. CONCLUSIONS: Home blood pressure monitoring and/or the behavioral intervention had little impact on medical resource use or costs over 2 years. Our analysis demonstrated that these interventions are cost-additive to the health care system and that patients' time costs are considerable.