Accurately measuring blood pressure (BP) requires choosing an appropriate BP cuff size.This study examined trends in mid-arm circumference (mid-AC) and distribution of BP cuff sizes using 1999-2002, 2003-2006, and 2007-2010 National Health and Nutrition Examination Survey (NHANES) data.NHANES uses a complex multistage probability sample design to select participants who are representative of the entire civilian, noninstitutionalized US population. The analytic sample consisted of 28 233 participants aged 20 years or older. Mid-AC and BP cuff sizes were analyzed across survey years by sex, age, race/ethnicity, hypertension, and diabetic status.Data from NHANES 2007-2010 show that the mean mid-AC for men was 34.2 cm and for women was 31.9 cm. Men showed a significant trend in mid-AC (from 33.9 cm in 1999-2002 to 34.2 cm in 2007-2010; P<0.05 for trend). In addition, 42.9% of men and 25.3% of women needed a large adult BP cuff and 1.9% of men and 2.8% of women needed thigh cuffs to be appropriately cuffed. Moreover, 52% of hypertensive men, 38% of hypertensive women, 59.1% of diabetic men, and 53.6% of diabetic women required the use of BP cuffs with sizes different from those of standard adult-sized BP cuffs for accurate BP measurement.There was an overall significant trend in the mean mid-AC in cm for men but not for women. On the basis of NHANES 2007-2010 data, ∼45% of adult men and ∼28% of adult women required the use of BP cuffs with sizes different from those of standard adult-sized BP cuffs for accurate BP measurement.