; for the PURE (Prospective Urban Rural Epidemiology) Study investigators IMPORTANCE Hypertension is the most important preventable cause of morbidity and mortality globally, yet there are relatively few data collected using standardized methods. OBJECTIVE To examine hypertension prevalence, awareness, treatment, and control in participants at baseline in the Prospective Urban Rural Epidemiology (PURE) study. DESIGN, SETTING, AND PARTICIPANTS A cross-sectional study of 153 996 adults (complete data for this analysis on 142 042) aged 35 to 70 years, recruited between January 2003 and December 2009. Participants were from 628 communities in 3 high-income countries (HIC), 10 upper-middle-income and low-middle-income countries (UMIC and LMIC), and 4 low-income countries (LIC). MAIN OUTCOMES AND MEASURES Hypertension was defined as individuals with self-reported treated hypertension or with an average of 2 blood pressure measurements of at least 140/90 mm Hg using an automated digital device. Awareness was based on self-reports, treatment was based on the regular use of blood pressure-lowering medications, and control was defined as individuals with blood pressure lower than 140/90 mm Hg. RESULTS Among the 142 042 participants, 57 840 (40.8%; 95% CI, 40.5%-41.0%) had hypertension and 26 877 (46.5%; 95% CI, 46.1%-46.9%) were aware of the diagnosis. Of those who were aware of the diagnosis, the majority (23 510 [87.5%; 95% CI, 87.1%-87.9%] of those who were aware) were receiving pharmacological treatments, but only a minority of those receiving treatment were controlled (7634 [32.5%; 95% CI, 31.9%-33.1%]). Overall, 30.8%, 95% CI, 30.2%-31.4% of treated patients were taking 2 or more types of blood pressure-lowering medications. The percentages aware (49.0% [95% CI, 47.8%-50.3%] in HICs, 52.5% [95% CI, 51.8%-53.2%] in UMICs, 43.6% [95% CI, 42.9%-44.2%] in LMICs, and 40.8% [95% CI, 39.9%-41.8%] in LICs) and treated (46.7% [95% CI, 45.5%-47.9%] in HICs, 48.3%, [95% CI, 47.6%-49.1%] in UMICs, 36.9%, [95% CI, 36.3%-37.6%] in LMICs, and 31.7% [95% CI, 30.8%-32.6%] in LICs) were lower in LICs compared with all other countries for awareness (P <.001) and treatment (P <.001). Awareness, treatment, and control of hypertension were higher in urban communities compared with rural ones in LICs (urban vs rural, P <.001) and LMICs (urban vs rural, P <.001), but similar for other countries. Low education was associated with lower rates of awareness, treatment, and control in LICs, but not in other countries. CONCLUSIONS AND RELEVANCE Among a multinational study population, 46.5% of participants with hypertension were aware of the diagnosis, with blood pressure control among 32.5% of those being treated. These findings suggest substantial room for improvement in hypertension diagnosis and treatment.