Recent guidelines recommending more aggressive blood pressure control in patients with chronic kidney disease have unknown impact. We assessed trends in and predictors of blood pressure control in 8829 adult National Health and Nutrition Examination Survey 1999-2006 participants with hypertension (self-report, measured blood pressure, or use of antihypertensive medications), without (n=7178) and with (n=1651) chronic kidney disease. Uncontrolled blood pressure was defined as follows: general definition, systolic blood pressure > or =140 mm Hg and diastolic blood pressure > or =90 mm Hg, and disease-specific definition, systolic blood pressure > or =130 mm Hg and diastolic blood pressure > or =85 mm Hg (1999-2002) and systolic blood pressure > or =130 mm Hg and diastolic blood pressure > or =80 mm Hg (2003-2006) for those with chronic kidney disease (estimated glomerular filtration rate: <60 mL/min per 1.73 m(2)) or diabetes mellitus (self-report). Proportions with uncontrolled blood pressure in 1999-2006 were greater in those with chronic kidney disease versus those without chronic kidney disease (51.5% versus 48.7% [general definition: P=0.122] and 68.8% versus 51.7% [disease-specific definition: P<0.001]). In those with chronic kidney disease, there were significant decreases in uncontrolled blood pressure over time (55.9% to 47.8% [general definition: P=0.011]). With adjustment for demographic, socioeconomic, and clinical variables, older age (P<0.001) and lack of antihypertensive treatment (P<0.001) were associated with uncontrolled blood pressure, regardless of chronic kidney disease status; nonwhite race (P=0.002) was associated in those without chronic kidney disease, whereas female sex (P=0.030) was associated in those with chronic kidney disease. Multiple medications (P<0.001) and angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers (P=0.001) were associated with less uncontrolled blood pressure. Although some improvement has occurred over time, uncontrolled blood pressure remains highly prevalent, especially in subjects with chronic kidney disease and in nonwhites, older persons, and women. Therapy appears suboptimal.