Every year millions of undocumented people who live and work in the United States file their income taxes. In fact it is against the law for them not to do so:
See the link below for an article relating to this topic
http://www.wptv.com/news/national/why-millions-of-undocumented-immigrants-pay-taxes
Shahzad Ahmed, Immigration Attorney, in his article titled “Your TAXES and IMMIGRATION Consequences” writes the following:
“If you have no legal status in the U.S. What if you have no legal status? Should you take advantage and forego your tax obligations? To the contrary, my opinion is to pay your taxes for the following reasons. You may become eligible for certain immigration benefits in the future, which require showing good moral character or attaining favorable discretion of the Immigration Judge or the USCIS. For example, if an illegal immigrant is placed in deportation proceedings, he or she may be eligible for Cancellation of Removal, which requires showing that the person has resided in the U.S. for 10 years and that he has had good moral character throughout those years. Having filed tax returns for those years can help establish both of these requirements.
Similarly, if Congress does pass the Immigration Reform we have been anxiously awaiting, then the undocumented immigrant may be required to prove physical presence and good moral character. Having filed tax returns may help prove these requirements.
If you do not have a social security number and wish to file taxes, you can obtain a Taxpayer Identification Number (TIN) from the IRS to file your taxes. So don’t delay filing your taxes”
See the link below to read the full article
http://www.nejamelaw.com/articles/taxes-and-immigration-consequences.html