Two-thirds of people over the age of 50 fear that they will develop the condition while just one in 10 said they were frightened about getting cancer.
When 500 adults aged over 50 from across the UK were asked which condition they feared the most, 68 per cent said dementia and 9.44 per cent said cancer.
Just 3.88 per cent said they were frightened about getting a heart condition and 0.73 per cent were concerned about diabetes.
There are around 800,000 people with dementia in the UK but as the population ages this figure is expected to soar. Symptoms can include memory loss and difficulties with thinking, problem-solving or language.
“As an increasing number of people are diagnosed with dementia more people are seeing the profound impact that it can have on both the individual as well as the wider family,” said Paul Green, director of communications at Saga, which conducted the survey.
Alison Cook, director of external affairs at the Alzheimer’s Society, said: “The possibility of losing the very essence of what makes you the individual that you are is a frightening prospect.
“But fear can mean people don’t get a diagnosis and can often miss the opportunity to access treatments and the time to make important decisions about their future.”
Commenting on the poll Hilary Evans, director of external affairs at Alzheimer’s Research UK, urged anyone concerned about dementia to speak to their GP or contact the Alzheimer’s Society