WASHINGTON — People view Hillary Rodham Clinton and Rudy Giuliani as the least religious of the major presidential candidates, according to a poll released Thursday. Mitt Romney was seen as most religious, but his Mormonism may hurt him with voters.

Seven in 10 in the nonpartisan Pew Research Center poll said they believe it is important for a president to have strong religious beliefs, including broad majorities of both parties. Most also see each major presidential hopeful as at least somewhat religious — important because people who view a candidate that way are likelier to have a favorable opinion of them.

Of those expressing an opinion on the candidates' beliefs, 46 percent said they consider Romney, a Republican contender, to be very religious, far more than any other candidate. Yet a quarter of all Republicans — including 36 percent of white evangelical Protestants — said they would be less likely to vote for a Mormon.

Romney spokesman Kevin Madden said the former Massachusetts governor has "the same hopes and aspirations for his country" as voters, adding, "Any sort of abstract aversion toward him because of his denomination will likely fade."

Giuliani, the former New York mayor, was considered very religious by 14 percent, while 16 percent said the same of Clinton, the Democratic New York senator.

Clinton has spoken often of her Methodist upbringing and said her religion helped hold her marriage together. Giuliani, a divorced Roman Catholic who favors abortion rights, has said his relationship with God is private.

"There are many things about Senator Clinton that people don't know, and one of those things is that she is a person of faith," said Clinton spokesman Phil Singer.

"We're encouraged by the support Mayor Giuliani continues to receive across the Republican Party," said Giuliani spokeswoman Maria Comella.

The survey found 31 percent of Republicans know of Giuliani's abortion-rights views. He is seen about equally favorably by Republicans who are, and are not, aware of that.

Half in the poll said the GOP is friendly toward religion while 30 percent said the same about the Democrats. It also found that while 38 percent said social issues like abortion will be very important in deciding their vote for president, about double said the same about the war in Iraq and domestic issues like the economy.

John C. Green, senior fellow at the Pew Forum on Religion and Public Life, said the poll showed a candidate's religion is "not always the most important factor, but one important factor" for voters.

The survey was conducted by the Pew religion forum and the Pew Research Center for the People and the Press. It involved telephone interviews with 3,002 randomly chosen adults conducted from August 1 to 18, and has a margin of sampling error of plus or minus 2 percentage points.