Achieving blood pressure (BP) control is associated with lower cardiovascular disease (CVD) risk, but less is known about CVD risk associated with sustained BP control over time. This observational analysis of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) was restricted to participants with 4 to 7 visits with systolic BP (SBP) measurements during a 22-month period (n=24,309). We categorized participants as having sustained BP control (SBP <140 mm Hg) at 100%, 75% to <100%, 50% to <75%, and <50% of visits during this period. Outcomes included fatal coronary heart disease (CHD)/nonfatal myocardial infarction (MI), stroke, heart failure (HF), a composite CVD outcome (fatal CHD/nonfatal MI, stroke, and HF), and mortality. Hazard ratios (HRs) for the association of category of sustained BP control for each outcome were obtained using proportional hazards models. SBP control was present among 20.0% of participants at 100%, 16.4% at 75% to less than 100%, 27.0% at 50% to less than 75%, and 36.6% less than 50% of visits. Compared to those with SBP control at 100% visits, adjusted HR (95% CI) among those with SBP control at < 50% of visits were 1.16 (0.93–1.44) for fatal CHD/nonfatal MI, 1.71 (1.26–2.32) for stroke, 1.63 (1.30–2.06) for HF, 1.39 (1.20–1.62) for the composite CVD outcome, and 1.14 (0.99–1.44) for mortality. Sustained SBP control may be beneficial for preventing stroke, HF, and CVD outcomes in adults taking antihypertensive medication.