The Prospective Studies Collaboration is a collaborative meta-analysis combining data from existing prospective observational studies that recorded both blood pressure and blood cholesterol at baseline and that followed participants for cause-specific mortality. Investigators from around the world have collaborated to combine data from 61 existing prospective studies involving a total of one million participants from Europe, North America, Australia, Israel, China and Japan. During 12.7 million person-years of follow-up there were 120 000 deaths involving more than 55 000 vascular deaths (12 000 stroke, 34 000 ischaemic heart disease [IHD], 10 000 other vascular) and more than 65 000 other deaths.