US Catholics also backed the Democratic party with 48 per cent supporting them compared to 33 per cent who supported the Republicans.
Sixty-six of Jews said they supported the Democrats, with just 24 per cent indicating a Republican preference, according to the survey.
The US Religious Landscape Survey, based on interviews with 35,000 people in the US, charts the changing influence of religious beliefs on public life.
Greg Smith, one of the report's authors, told Al Jazeera that political attitudes among many religious groups, including Evangelical Christians, were shifting.
"The two political parties have opportunities within religious groups that they may not have had in the past."
Smith said that the decline in support for Republicans among Evangelicals was likely to be a reflection of wider dissatisfaction with the Bush administration.
The report argues that while relatively few people - 14 per cent - cite religious beliefs as the main influence on their political thinking, religion still plays a powerful indirect role.
Good and evil
Nine out of 10 people in the US believe in a kind of God, according to the survey.
Of those who pray regularly, around a third - 31 per cent -- said God answers their prayers at least once a month, and one in five Americans said they receive direct answers to prayer requests at least once a week, the report said.
Seventy-four per cent of those interviewed said they believed in heaven as a place where people who have led good lives are rewarded, while only about six in 10 believed in hell as a place where those who committed evil acts and are unrepentant face eternal punishment.
Fifty-seven per cent of Evangelical church attenders said they believe many religions can lead to eternal life, in conflict with traditional evangelical teaching.
In all, 70 per cent of Americans with a religious affiliation shared that view, and 68 per cent said there is more than one true way to interpret the teachings of their own religion.
Analysts said that this hinted that people in the US were becoming more tolerant of each other's religious beliefs.
"There's a growing pluralistic impulse toward tolerance and that is having theological consequences," D Michael Lindsay, a sociologist of religion at Rice University said.