The increase is less than the $9 increase previously projected. Part B participants currently pay $99.90, usually deducted directly from their Social Security checks.
Part B covers outpatient care.
AARP noted the increase "will eat up nearly 25 percent of the monthly Social Security cost of living adjustment," which amounted to 1.7 percent for 2013.
David Certner, AARP legislative policy director, said the seniors' lobbying group opposes any deficit reduction plan that would reduce Social Security benefits by adopting the Chained Consumer Price Index, which uses a different formula to calculate inflation.
"The COLA is already based on an index that under-reports rapidly increasing healthcare costs and today's announcement of a $5 premium increase is further proof that these costs are being disproportionately felt by seniors," Certner said in a release. "With millions of America's seniors struggling with higher expenses -- particularly higher healthcare costs -- we need to do more to lower costs across the health care system and avoid further cost-shifting to seniors."