Less than half of American voters know President Barack Obama is Christian, while 17 percent think he is a Muslim, according to the new study by the Pew Forum for Religion and Public life.
The Washington Post reported only 49 percent of US voters know that their president is Christian.
30 percent of conservatives thought Obama was a Muslim, while about a third of the most conservative Republicans, some 34 percent, agreed.
Surprisingly, the Pew survey found that in 2008 only 16 percent of conservatives believed that Obama was a Muslim, which means their misperception of the president's religion have increased while he's in office.
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Overall, about 45 percent, or less than half of voters are comfortable with Obama’s religion, while 19 percent are uncomfortable.
"Most voters continue to say it is important for a president to have strong religious beliefs. But voters have limited awareness of the religious faiths of both Mitt Romney and Barack Obama," the study concluded. "And there is little evidence to suggest that concerns about the candidates’ respective faiths will have a meaningful impact in the fall elections."
The study also found that of the 60 percent of voters who know that Romney is a Mormon, a majority said it doesn't matter.