Medicare's basic monthly premium will go up next year, but less than previously predicted.
Most seniors will pay an additional $3.50 a month, instead of the $10.20 increase predicted in May.
Officials said Thursday the 2012 Part B for outpatient care will be $99.90 a month for 2012 instead of this year's charge of $115.40.
Consequently, the three-fourths of Medicare recipients whose premiums have been frozen at the 2008 rate will keep more of next year's Social Security increase.
Obama administration hailed the news as proof Medicare is under sound management.
"Thanks to the Affordable Care Act, Medicare is providing better benefits at lower cost," Health and Human Services Secretary Kathleen Sebelius said.
But GOP lawmakers warned the brunt of "Obamacare's" Medicare cuts is still to come.
"More importantly, lower Medicare premiums are being driven by lower than average Medicare spending due to the slow economy" - not the health care law, said Antonia Ferrier, a spokeswoman for Sen. Orrin Hatch, R-Utah.