Firefighters face a "perfect storm," he told more than 3,000 firefighters at the annual meeting of the International Association of Fire Fighters. He cited the effects of the recession, budgetary policies in Congress and efforts to dismantle the collective-bargaining rights of firefighters and other public employees around the country.
"We should be cutting your taxes and helping cities and states maintain their fire service," Biden said.
He said Republicans look at firefighters and see an easy place to cut budgets.
"I don't think he understands what you're about," Biden said of Republican presidential candidate Mitt Romney. He added: "This is not your father's Republican Party. They act like you're the community's problem."
Biden, however, avoided the contract dispute in Philadelphia between firefighters and Democratic Mayor Michael Nutter, an outspoken supporter of re-electing President Barack Obama. Firefighters plan a City Hall protest on Thursday.
After the speech, Romney's campaign issued a statement from a retired Philadelphia firefighter who said Obama is out of touch with the struggles of middle-class people.
"Joe Biden can come to Philadelphia, and he can try and tell the hard-working men and women of this city that he understands what we've been going through," said Fred Donnelly, a retired battalion chief. "But no matter what he says, he can't cover up the words of the president."
Donnelly cited Obama's recent comments about the private sector "doing fine" and the success of small-business owners, which Republicans have been using against the president.
"We know that he is simply out of touch with the struggles that middle-class Americans are going through, and that he doesn't understand what drives the American economy," Donnelly said of Obama.