As policymakers consider ways to slow the growth in Medicare spending as part of broader efforts to reduce the federal debt or offset the cost of other spending priorities, some have proposed to increase beneficiary contributions through higher Medicare premiums. Some proposals would increase Medicare premiums paid by all beneficiaries, while others would raise premiums only for beneficiaries with higher incomes. This issue brief explains provisions of current law that impose income-related premiums under Medicare Part B and Part D, describes recent proposals to modify these requirements, and analyzes the potential implications for the Medicare population.