WASHINGTON – Senator Kerry took on President Bush’s health-care proposals yesterday in his first major speech since losing to Mr. Bush in November, saying the plans won’t meet the needs of children and low-income families who don’t have health coverage.

“Today the president is in Ohio addressing health care, but his effort is the same window dressing, avoidance of reality that we’ve seen the last four years,” the Massachusetts Democrat said.

Mr. Bush was in Cleveland yesterday talking about a plan for more computerization of medical records as a way to reduce medication errors and cut costs.

Mr. Kerry spoke at a luncheon, sponsored by the private group Families USA, that at times resembled one of his election campaign stops. He joked, posed for pictures, and hugged supporters.

As on the campaign trail, he recounted stories of people he had met who were struggling to pay their health-care bills or going without care so they could buy other necessities.

Recounting a meeting with Erie, Pa., resident Albert Barker, Mr. Kerry said the man had a heart attack and later lost his health coverage, so his wife would pray every day that nothing else happened.

“We shouldn’t have to rely on a faith based initiative for health care,” Mr. Kerry said, taking another swipe at Mr. Bush, who has pushed for more funding for religious programs.

Republican National Committee spokesman Danny Diaz questioned Mr. Kerry’s commitment to health care, saying he was “long on political attacks and short on credibility.”

“Over the course of Senator Kerry’s two decades in Congress, he has introduced virtually no health care legislation,” said Mr. Diaz.

Mr. Kerry is pushing a proposal that would provide health care to all children through an expansion of the Medicaid program. The federal government would absorb states’ costs for children at or below poverty level, to encourage states to expand coverage to children in families that make less than about $47,000. It would cover children up to the age of 21. It is a legislative long shot in the Republican-controlled Senate.

Also yesterday, Senator Clinton, whose career as first lady was scarred by a fight over health care, waded back into the fight yesterday by saying millions of poor and elderly Americans are at risk of losing benefits they now get from Medicaid and Medicare.

Mrs. Clinton, in a speech to Families USA, a nonprofit consumers group, warned of dire consequences from changes made to the Medicare program for the elderly as well as expected alterations in Medicaid funding for the poor.

The Bush administration has signaled it wants to make changes to the Medicaid program, a growing source of financial frustration for state and local governments who pay part of the costs to provide health care to the poor and working poor.

Since 2001, Medicaid enrollment has grown by almost a third, according to a Kaiser Family Foundation study. In fiscal year 2004, 21 states reduced or restricted those who can receive Medicaid, and 14 now plan to do so.