I am in the US on a L1 visa from May 2010. My spouse also came to US with me as a L2 dependent and returned to India in Oct2010. And I changed my status from married to single in Oct2010.How do I need to file my tax returns - as single and add my spouse as dependent or file as married jointly? My spouse has a SSN.

You can file joint return as residents for 2010. Both of you must report worldwide income. Your U.S. Tax Return: The U.S. Visas (http://taxipay.blogspot.com/2008/08/us-visas.html)