Midnight Rule Act

Midnight Rule Act - Amends federal civil service law to provide that a midnight rule (i.e., a rule adopted by an agency within the final 90 days a President serves in office) shall not take effect until 90 days after the agency head is appointed by the new President. Makes exceptions if the President serving his final term makes a determination by executive order, and submits written notice to Congress, that the rule should take effect because it is: (1) necessary because of an imminent threat to health or safety or other emergency; (2) necessary for the enforcement of criminal laws; (3) necessary for national security; or (4) issued pursuant to any statute implementing an international trade agreement.

Provides that an exercise by the President of such authority shall have no effect on existing provisions governing congressional disapproval of agency rules.

Authorizes the agency head appointed by the new President to disapprove of a midnight rule (by publishing a statement of disapproval in the Federal Register and sending a notice of disapproval to the congressional committees of jurisdiction) no later than 90 days after being appointed.

Makes this Act applicable to any rule adopted on or after October 22, 2008.