Medicare Advantage and Prescription Drug Accountability Act of 2005

Medicare Advantage and Prescription Drug Accountability Act of 2005 - Amends title XVIII (Medicare) of the Social Security Act to require the contract with an Medicare Advantage (MA) organization to provide for a minimum loss ratio (aggregate average benefits that are at least a minimum ratio of the aggregate average revenues collected under the contract) and a maximum administrative cost ratio (aggregate average administrative costs that do not exceed a maximum ratio of the aggregate average revenues collected under the contract).

Requires each contract with a Medicare+Choice organization to grant the Secretary of Health and Human Services the right to audit and inspect any books and records of the organization for compliance with such ratio and related administrative cost requirements.

Applies such requirements to contracts with prescription drug sponsors under Medicare part D (Voluntary Prescription Drug Benefit Program).

Prescribes requirements for financial transparency of MA plans.

Renders an election to enroll with an MA plan ineffective unless the election form is signed by the individual and specifically acknowledges specified plan features.

Applies such requirements to prescription drug plans under Medicare part D.

Directs the Secretary to transmit to Congress annual MA accountability and prescription drug accountability reports.

Requires periodic audits by the departmental Inspector General of the Secretary's determinations about the acturial equivalency of MA plans.

Requires each prescription drug plan sponsor with respect to a prescription drug plan, and each MA organization with respect to an MA-PD plan, to report annually to the Inspector General on drug claims rejections and reversals on appeal.

Directs the Secretary to appoint a Medicare prescription drug ombudsman.