An Individual Taxpayer Identification Number (ITIN) is a tax processing number issued by the Internal Revenue Service (IRS) to individuals who are required to have a U.S. taxpayer identification number but who do not already have, and are not eligible to obtain, a Social Security Number (SSN) from the Social Security Administration (SSA).

Taxable fellowship or scholarship recipients classified as stipend recipients (not wage earners) are required to obtain an ITIN. Those with an offer of employment or a wage earner role must apply for an SSN instead of an ITIN.

Learn more about the differences between International Wage Earners vs. Stipend Recipients.

What is an ITIN?

An ITIN is a tax processing number issued by the Internal Revenue Service (IRS). It is a nine-digit number that always begins with the number 9, in the format: 9xx-xx-xxxx. 

The IRS issues ITINs to foreign nationals who are required to have a U.S. taxpayer identification number, but who do not have, and are not eligible to obtain, a Social Security Number (SSN). Additional information about the ITIN process is available on the IRS website.  

The IRS issues ITINs to help individuals comply with U.S. tax laws, and to provide a means to process and account for tax returns and payments for those not eligible for Social Security numbers. You may be issued an ITIN regardless of immigration or tax status because both resident aliens and nonresident aliens for tax purposes may have a U.S. filing or reporting requirement under the Internal Revenue Code. ITINs do not serve any purpose other than federal tax reporting.  

Visit our Filing your U.S. Taxes page for more details about tax filing requirements.

Important Note: the 999/000 number that you are asked to enter in Workday to substitute for a valid SSN or ITIN is not a valid SSN or ITIN. It is a dummy ID used during the process of applying for an SSN or ITIN.  

Who needs an ITIN?

Foreign nationals with a federal tax reporting or tax filing requirement need an ITIN if they do not qualify for an SSN.  

One category of foreign nationals who need an ITIN are those receiving a taxable scholarship, fellowship or grant from WashU that is paid as a stipend rather than a salary or a wage. If this applies to you, we encourage you to apply for an ITIN as soon as possible.  

Another category is anyone who files a U.S. federal tax return. Typically, this includes anyone with taxable income or individuals who need to claim benefits of a tax treaty between their home country and the U.S.  

Individuals who need to file Form 8843 only and do not have taxable income to report to the Internal Revenue Service (IRS) do not need to apply for an ITIN.  

How to apply

There are several different ways in which you can apply for an ITIN. The way you choose to apply will depend on your circumstances and preference. Below, we outline the most common options utilized by WashU students and scholars.  

Regardless of which method you use, we always recommend that you apply for an ITIN as early as possible. ITIN processing times may be longer during certain times of the year, which can impact when you can complete federal tax filing and claiming of tax treaty benefits, if applicable.  

After the ITIN application is submitted

ITIN processing times vary by season: up to approximately 11 weeks during tax filing season (January–April) and around 7 weeks at other times. While faster processing is possible, plan ahead to account for potential delays.

Note: If you receive a rejection of your ITIN application, reach out to us at oiss@wustl.edu for additional information. Your next steps may vary on your circumstances, but usually you must reapply for an ITIN if you are rejected.  

If you receive a request for additional evidence from the IRS, respond right away and before the deadline listed on the IRS notice. If you need assistance, reach out to oiss@wustl.edu.  

Once your application is approved and you receive your ITIN, you must enter in Workday if you are receiving a WashU stipend. Follow this Workday tutorial to add the ID in Workday.  

ITIN and SSN

If you become eligible for an SSN while your ITIN application is pending or after you’ve received an ITIN, you can apply for an SSN. You may have both numbers at the same time if your circumstances allow it. You do not have to report your SSN eligibility to the IRS.  


Disclaimer Statement

The Office for International Students and Scholars (OISS) provides resources and content for general informational and educational purposes only. This information does not replace advice from the Internal Revenue Service (IRS) or a qualified tax professional. The information provided is subject to change. If your immigration status has changed in the past year or you have a complex tax situation, please consult the IRS or a qualified tax accountant.