The Medicare Part B premium will rise by $3.50 monthly to $99.90 monthly beginning Jan. 1, according to the Centers for Medicare & Medicaid Services. This is the first increase in the Part B premium in two years.

For Medicare participants who first enrolled in 2010 and 2011, and have been paying as much as $115.40 monthly, the monthly premium will drop to to $99.90.
  
Because Medicare premiums are adjusted for higher-income retirees, some beneficiaries (fewer than 5 percent of all beneficiaries) will pay higher premiums in 2012, reaching as high as $319.70 monthly for individuals whose adjusted gross income exceeds $428,000 (married couple).

Only higher-income beneficiaries will pay an increased amount for Medicare Part D prescription drug coverage in 2012.
  
Additional information on Medicare coverage, including specific benefits and deductibles, can be found at http://www.medicare.gov/