Ninth Circuit Court of Appeals En Banc Procedures Act of 1999 - Amends the Federal judicial code to allow 40 percent or more of the circuit judges of the Ninth Circuit Court of Appeals (Court) who are in regular active service to order a hearing or rehearing before the court en banc for such circuit (currently, a majority must vote affirmatively to rehear a case en banc).

Provides that a majority of the judges shall be required to sit on a court en banc for such circuit (currently, 11 judges must sit on a court en banc).

Requires that: (1) the Court be organized into no fewer than three administrative units based on geographic regions; (2) each panel of the Court be assigned to an administrative unit; and (3) in any case or controversy heard by any panel of an administrative unit, at least one judge of that unit be assigned to that panel (currently, there is no requirement that the Court have geographical representation on its panels).