Postdocs who are foreign nationals may want to review the materials posted in the Nonresident Aliens section of the Payroll Services site. Postdocs who are nonresident aliens for tax purposes (excluding permanent residents with green cards) must use Glacier software, which will determine the correct amount of federal tax to be withheld from their paychecks. An email with a password and information about Glacier should arrive two to three weeks after you begin your postdoctoral position. If you are a nonresident alien and you have not received Glacier information, please contact the Tax Office at firstname.lastname@example.org. It is important to establish a record in the Glacier system because you may qualify for the benefit of a tax treaty if one exists between your home country and the United States. More information about U.S. taxes and CINTAX, a tax return preparation software program available for your free use, is available from the Office of International Affairs.