Instead, those between the age of 18-24 say that the UK is a country with no religious identity.
This contrasts sharply with the three-quarters of those over 65 who say that the UK is a Christian country.
The majority of millennials did say that it is important for there to be an understanding of religion in society.
More than half (52 per cent) agreed that it is important for UK politicians to have a good understanding of religions in the UK.
Half also agreed that understanding religion is important to tackling terrorism.
"In some of the questions we asked, adults aged between 18-24 and adult aged 65+ answered at opposite ends of the scale, indicating marked differences between generations in perceptions of religion and belief," says Katie Harrison, Director of the new Faith Research Centre at ComRes.
"We're seeing a strong interest in understanding the attitudes and needs of people in their 20s, especially in our faith research work."
The poll was conducted at the start of January by ComRes. More than 2,000 people took part in the research.