Raised blood pressure is the biggest single contributing risk factor to death and the burden of disease worldwide. However, international data suggest that fewer than half of those with hypertension are aware of their condition. In May 2017, the International Society of Hypertension and the World Hypertension League are leading a global initiative - May Measurement Month (MMM) - to raise awareness of the importance of screening. MMM will be a cross-sectional survey of men and women aged ≥18 who have not had their BP measured since 30 April 2016.