Addressing a town-hall meeting in Iowa, the former New York mayor was asked whether he considered himself a "traditional, practicing Roman Catholic." An audience member also called on Giuliani to discuss the role his faith played in making decisions on issues such as abortion.
"My religious affiliation, my religious practices and the degree to which I am a good or not so good Catholic, I prefer to leave to the priests," Giuliani said. "That would be a much better way to discuss it. That's a personal discussion and they have a much better sense of how good a Catholic I am or how bad a Catholic I am."
Giuliani is alone among the major Republican candidates in favoring abortion rights, a practice that the Catholic Church opposes. Some church officials have suggested that candidates who favor abortion rights should be denied the sacrament of communion.
On a personal level, Giuliani has been married three times, with one annulment and one divorce. Catholics who are divorced and have remarried are not permitted to receive communion.
In two days of campaigning in Iowa, Giuliani has sought to focus attention on adoptions and improving the quality of life for children. Yet, he has faced questions about his personal life, dealing with queries about his 17-year-old daughter's political preference on Monday and his religion on Tuesday.
The first questioner at the town-hall meeting mentioned President Bush's success in winning the support of Catholic voters and pushed Giuliani to explain his religious faith.
"That's a matter of individual conscience," Giuliani said. "I don't think there should be a religious test for public office."
That answer didn't satisfy questioner Thomas Fritzsche of Davenport, Iowa.
"Of course he didn't answer my question," said Fritzsche.
Giuliani said he's the only Republican who can compete throughout the country without writing off traditionally Democratic states.
"I can make this campaign a nationwide campaign," Giuliani said. "We have only run in certain states."
Giuliani met privately with law enforcement officials who run anti-drug programs, and he told about 300 people at the town hall meeting that it was essential to expand the nation's anti-drug effort. He said no other presidential candidates has his experience fighting drugs.
"It's something I understand really well," said Giuliani, noting his experience as a prosecutor and mayor of New York City. "I've been doing this kind of work longer than I've been in politics."
Giuliani also offered his prediction about whom Republicans will face in the fall election.
"I suspect it will be a Hillary Clinton-Barack Obama ticket," he said. "Their views are pretty much the same."