If you worked and earned money from a US source in 2011 you will need a Social Security Number (SSN) in order to file your tax return.

If you did not work and earn any money in 2011 from a US source you do not need a Social Security Number (SSN) or Individual Taxpayer Identification Number (ITIN).

Dependents who are being claimed as deductions on an income tax return, must have a SSN or an ITIN. A dependent in most cases can only be claimed on a Resident Alien tax return. However spouses from Canada, Mexico, Korea, Japan and Indian (students, not researchers from India) may be eligible to be claimed on a Non-Resident Alien return. In order to determine which kind of number your dependents need, use the following as a guide:

Materials and instructions to apply for either of these numbers are available at the UC International Services front desk.