The Bush administration announced a day earlier that monthly premiums for a portion of the program for the elderly and disabled will rise $11.60 next year, to $78.20. The 17 percent increase is the largest in the program's 40-year history.
Kerry pointed to Bush's promise in his convention speech to make Medicare stronger. The speech and the increase are highlighted in a new Kerry campaign television ad to start running Tuesday in battleground states.
"On the day after saying he'd strengthen Medicare, Medicare premiums go up for senior citizens 17 percent," Kerry told supporters at a rally in this electorally important state.
"You bet they're not," Kerry said, answering his own question. "They're going to send the bill to our senior citizens. They're going to send the bill to all of you people."
Kerry also blamed the Bush administration for driving up health care costs with its refusal to let Medicare negotiate lower-price drug purchases and its opposition to people buying cheaper medications in Canada.
Bush campaign spokesman Steve Schmidt said health care costs are high because Kerry and other Democrats have refused to curb medical malpractice lawsuits and limit monetary damages.
That opposition is "raising the cost of health care for Americans, and is forcing doctors like ob/gyns to leave their practice," Schmidt said.
In Steubenville, an Ohio River town near the Pennsylvania and West Virginia borders, Kerry said Bush's decision to remove tariffs on steel imports midway through a three-year program was an example of the flip-flopping Republicans accuse him of doing.
"He broke his promise to the people of Ohio and West Virginia and Pennsylvania," Kerry said at the closing rally of his Ohio campaign swing.
Bush also stumped Saturday in Ohio. He won the state in 2000, but is vulnerable here on jobs. The state has lost more than 200,000 since Bush took office. No Republican has been elected president without winning Ohio.
Kerry appealed to gun owners, saying he's been a hunter "all my life." After leaving Akron, he demonstrated his shooting skills in Edinburg, where he shot four of 10 traps. Kerry also surveyed flood damage in Lisbon, and met with a group of steelworkers in Stratton.
Several dozen Bush supporters greeted Kerry in Steubenville with signs favoring a second Bush term and opposing the Catholic Kerry's support for abortion rights.
Kerry was headed to Pittsburgh for a day of rest Sunday at his wife's estate.