© 2016 Wiley Periodicals, Inc. Many adults with elevated clinic blood pressure (BP) have lower BP when measured outside the clinic. This phenomenon, the "white-coat effect," may be larger among older adults, a population more susceptible to the adverse effects of low BP. The authors analyzed data from 257 participants in the Jackson Heart Study with elevated clinic BP (systolic/diastolic BP [SBP/DBP] ≥140/90 mm Hg) who underwent ambulatory BP monitoring (ABPM). The white-coat effect for SBP was larger for participants 60 years and older vs those younger than 60 years in the overall population (12.2 mm Hg, 95% confidence interval [CI], 9.2-15.1 mm Hg and 8.4 mm Hg, 95% CI, 5.7-11.1, respectively; P=06) and among those without diabetes or chronic kidney disease (15.2 mm Hg, 95% CI, 10.1-20.2 and 8.6 mm Hg, 95% CI, 5.0-12.3, respectively; P=04). After multivariable adjustment, clinic SBP ≥150 mm Hg vs <150 mm Hg was associated with a larger white-coat effect. Studies are needed to investigate the role of ABPM in guiding the initiation and titration of antihypertensive treatment, especially among older adults.