BACKGROUND Issues surrounding end of life care, such as how aggressively to treat life threatening medical conditions in patients with dementia and when, if ever, to withhold or withdraw treatment require further scrutiny and debate. METHODS We conducted a cross-sectional survey to elicit the views of the general public on euthanasia and life-sustaining treatments in the face of dementia. RESULTS Seven hundred and twenty-five members of the general public completed this questionnaire throughout London and the South East. In the face of severe dementia, less than 40% of respondents would wish to be resuscitated after a heart attack, nearly three-quarters wanted to be allowed to die passively and almost 60% agreed with physician assisted suicide. Respondents were more likely to be in favour of life-sustaining treatments for their partner than for themselves and the opposite was true regarding euthanasia. White respondents were significantly more likely to refuse life-sustaining treatment and to agree to euthanasia compared with black and Asian respondents. CONCLUSIONS Our survey suggests that a large proportion of the UK general public do not wish for life-sustaining treatments if they were to become demented and the majority agreed with various forms of euthanasia.