More than 1,000 people in Scotland had their blood pressure checked as part of the Blood Pressure Association's (BPA) UK-wide Know Your Numbers Week.
The charity found that almost a third (29 per cent) gave high blood pressure readings.
However, this was a lower percentage than elsewhere in the UK. Northern Ireland had the highest incidence of high blood pressure readings, at 36 per cent of those tested, with England following closely behind at 34 per cent and Wales at 32 per cent.
Every day, 350 people across the UK suffer a preventable heart ttack or stroke caused by high blood pressure.
The condition is also a major risk factor for heart and kidney disease, and there is increasing evidence that it is also a risk factor for vascular dementia.
The BPA also said it found a "staggering" lack of awareness of blood pressure, with 77 per cent of those tested in Scotland admitting they did not know their blood pressure numbers.
Professor Graham MacGregor, chairman of the BPA, said: "High blood pressure is a symptomless condition which causes half of all strokes and heart attacks in the UK, so it is extremely worrying that almost a third of the adults we tested in Scotland had high blood pressure readings."
Prof MacGregor went on: "We at the Blood Pressure Association urge everyone in the UK to be blood pressure aware and get to know how they can achieve a healthy blood pressure, so that we can stop the needless death and disability caused by this 'silent killer'."