Good Morning,
I worked for a few months in the US(California) in 2010 as Self Employed. I've lived Full Time in Canada and worked from home. My wife is Canadian, and only worked here in Canada. She doesn't have a Social Security #. If I want to file Jointly, can I use her Social Insurance # in lieu of SS #? Thanks for the tips.
JS

If she is a Canadian citizen then all she needs is your social insurance number. All Canadians have one. I don't understand what you asking. When you file jointly in Canada you use the social insurance number. Do you mean you are filing US taxes as well, jointly ? I don't think you can use her Canadian social insurance number to file. She wouldn't have a social security #(US) unless she had a green card.

Please make this clear. Thanks.

Tick

Hi, Sorry for the confusion. The ? Is regarding my US taxes. I generated a bit of US Income working from Canada as a S/E Loan Officer, so I need to file a 1040, or 1040 NR. So, my question is, which filing status should I use. On the 1040, a SS# is required, but she doesn't have one. She had no US income to report.. only Canadian. Hope that clears things up. Thanks, J

You can't file a U.S. return as a joint return if your wife didn't work in the U.S. and have a Federal Taxpayer I.D. number. If you were in the U.S. for less than 180 days, look up the terms of the US-Canada OECD Tax Treaty.
You may not have significant U.S. tax liability.