The deadline for filing a petition with the Tax Court depends on the type of case. For deficiency cases, the petition must be filed within 90 days (150 days if the notice is addressed outside the United States) after the Notice of Deficiency is mailed by the IRS. For collection due process (CDP) cases involving liens or levies, the petition must be filed within 30 days after the IRS determination is mailed. For more information, see 26 U.S. Code § 6213 () and 26 U.S. Code § 6330 ().