21st Century Medicare Act

21st Century Medicare Act - Amends title XVIII (Medicare) of the Social Security Act (SSA) to establish: (1) a Voluntary Prescription Drug Delivery Program under a new part D; and (2) a Prescription Drug Account in the Federal Supplementary Medical Insurance Trust Fund. Directs the Secretary of Health and Human Services (HHS) to establish: (1) within the Department of HHS the Medicare Competitive Agency, headed by an Administrator charged with carrying out Medicare parts D and C (Medicare+Choice); and (2) within the Agency an Office of Beneficiary Assistance to carry out functions relating to Medicare beneficiaries. Creates a Medicare Ombudsman in such Office. Establishes within the Medicare Competitive Agency the Medicare Competitive Policy Advisory Board.

Directs the Administrator of the Medicare Competitive Agency to study and report to Congress on the need for rules relating to permitting individuals who are enrolled under Medicare part B (Supplementary Medical Insurance) but are not entitled to benefits under Medicare part A (Hospital Insurance) to buy into the Medicare voluntary prescription drug delivery program.

Amends SSA title XVIII with respect to the Federal Supplementary Medical Insurance Trust Fund to require the Board of Trustees of the Trust Fund to submit to Congress a combined report on the operation and status of the Trust Fund and the Federal Supplementary Medical Insurance Trust Fund, including the Prescription Drug Account within such Trust Fund.

Expands the membership and duties of the Medicare Payment Advisory Commission (MEDPAC).

Directs the Secretary to establish procedures under which each eligible beneficiary shall be entitled to elect to receive enhanced Medicare benefits under a new Medicare part E (Enhanced Medicare Benefits) instead of the benefits under Medicare parts A and B.

Sets forth rules relating to Medicare supplemental insurance (Medigap) policies that provide prescription drug coverage, such as prohibiting the sale, issuance, and renewal of policies that provide prescription drug coverage to part D enrollees.

Amends SSA title XVIII part C to provide for competition under the Medicare+Choice program and part D and E benefits under competitive Medicare+Choice plans.