Pension Benefits Protection Act of 2003

Requires ERISA, the Code, and the Age Discrimination Act of 1967 to be applied and administered without regard to certain proposed regulations of the Secretary of the Treasury that relate to reductions of accruals and allocations because of the attainment of any age, and to application of nondiscrimination cross-testing rules to cash balance plans.

Amends ERISA and the Code to protect certain DB plan participants from forced conversions to hybrid DB plans by plan amendments which change the way the accrued benefit to participants or beneficiaries are expressed and which reduce the rate of future benefit accrual of one or more participants. Requires employers, at the time such amendment takes effect, to provide employees who have attained 40 years of age or 10 years of service with certain notices and an election upon retirement to receive benefits as determined either under the plan in effect at time of retirement or under the plan in effect immediately before the plan amendment.

Sets forth a formula to determine when a plan amendment adopted by a large (100 or more participants) DB plan shall be treated as wearing away accrued benefits.