Abstract BACKGROUND Recent US blood pressure (BP) guidelines recommend using ambulatory BP monitoring (ABPM) or home BP monitoring (HBPM) to screen adults for masked hypertension. However, limited evidence exists of the expected long-term effects of screening for and treating masked hypertension. METHODS We estimated the lifetime health and economic outcomes of screening for and treating masked hypertension using the Cardiovascular Disease (CVD) Policy Model, a validated microsimulation model. We simulated a cohort of 100,000 US adults aged ≥20 years with suspected masked hypertension (i.e., office BP 120–129/<80 mm Hg, not taking antihypertensive medications, without CVD history). We compared usual care only (i.e., no screening), usual care plus ABPM, and usual care plus HBPM. We projected total direct healthcare costs (2021 USD), quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios. Future costs and QALYs were discounted 3% annually. Secondary outcomes included CVD events and serious adverse events. RESULTS Relative to usual care, adding masked hypertension screening and treatment with ABPM and HBPM was projected to prevent 14.3 and 20.5 CVD events per 100,000 person-years, increase the proportion experiencing any treatment-related serious adverse events by 2.7 and 5.1 percentage points, and increase mean total costs by $1,076 and $1,046, respectively. Compared with usual care, adding ABPM was estimated to cost $85,164/QALY gained. HBPM resulted in lower QALYs than usual care due to increased treatment-related adverse events and pill-taking disutility. CONCLUSIONS The results from our simulation study suggest screening with ABPM and treating masked hypertension is cost-effective in US adults with suspected masked hypertension.