Ninth Circuit Judgeship and Reorganization Act of 2005 - Amends the federal judicial code to divide the Ninth Judicial Circuit into the Ninth Circuit (to be composed of California, Guam, Hawaii, and the Northern Mariana Islands), the Twelfth Circuit (to be composed of Arizona, Nevada, Idaho, and Montana), and Thirteenth Circuit (to be composed of Alaska, Oregon, and Washington State).

Requires the President to appoint, with the advice and consent of the Senate, five additional circuit judges for the new Ninth Circuit and two temporary judges for the former Ninth Circuit.

Specifies the locations where the new circuits are to hold regular sessions.

Assigns active circuit judges of the former Ninth Circuit to the new circuits based on their current duty station. Allows senior circuit judges of the former Ninth Circuit to elect assignment to any of the three new circuits.

Specifies the disposition of cases pending in the former Ninth Circuit before the effective date of this Act as follows: (1) proceedings in matters that have been submitted for decision shall continue without regard to this Act; (2) matters not yet submitted for decision must be transferred to the court to which they would have been submitted under this Act; and (3) proceedings on petitions for rehearing or rehearing en banc that have been submitted or decided shall continue without regard to this Act.

Authorizes the temporary assignment of the circuit and district judges of the former Ninth Circuit among the new circuits. Authorizes administrative coordination between any two contiguous circuits among the new circuits.

Directs that the former Ninth Circuit shall cease to exist for administrative purposes two years after enactment of this Act.