Hypertension is a major global health problem, but prevalence rates vary widely among regions. To determine prevalence, treatment, and control rates of hypertension, we measured conventional blood pressure (BP) and 24-hour ambulatory BP in 6546 subjects, aged 40 to 79 years, recruited from 10 community-dwelling cohorts on 3 continents. We determined how between-cohort differences in risk factors and socioeconomic factors influence hypertension rates. The overall prevalence was 49.3% (range between cohorts, 40.0%-86.8%) for conventional hypertension (conventional BP >= 140/90 mm Hg) and 48.7% (35.2%-66.5%) for ambulatory hypertension (ambulatory BP >= 130/80 mm Hg). Treatment and control rates for conventional hypertension were 48.0% (...