Medicare is the government-administered program that funds healthcare for people aged 65 or older.
A government report released on Thursday showed the program's trust fund was not projected to exhaust its funds until 2029, 12 years later than forecast last year, as a result of cost cuts stemming from Obama's healthcare reform law.
The steps we took this year to reform the healthcare system have put Medicare on a sounder financial footing, Obama said in his weekly radio and Internet address.
Reform has actually added at least a dozen years to the solvency of Medicare -- the single longest extension in history -- while helping to preserve Medicare for generations to come.
The same report, however, showed the deep recession ate into receipts for another major program for retired Americans, Social Security, helping push it into deficit for the first time in 27 years.
Obama did not mention that aspect of the report in his address.
The president, a Democrat, is working hard to highlight his administration's successes ahead of November congressional elections that are expected to see big Republican gains, potentially changing the balance of power in Congress.
Healthcare reform, his biggest legislative achievement, was opposed by Republicans and remains controversial among many Americans.
In his address Obama said reform was already improving senior citizens' benefits.
Beginning next year, preventive care -- including annual physicals, wellness exams, and tests like mammograms -- will be free for seniors as well, he said. That will make it easier for folks to stay healthy.
Republicans charge that the healthcare bill vastly expanded the reach of government and was too costly.
Both parties want the support of older Americans, who are traditionally more likely to show up at the polls on voting day, making them an especially important constituent group.