How do I petition my mother to become an American citizen?

Your first step would be to file an immigrant visa petition on her behalf. Then you need to consult with an attorney to determine her future eligibility to adjust her status to that of a Lawful Permanent Resident.

Generally, the starting point is to file an I-130. if she entered legally, you might also be able to have her file an I-485.

You must petition for her on I-130 form. That is the start. You must assemble certain documents to support this petition. You can go on-line USCIS site and read about what documents you need to present. Then, you need to file some other forms to adjust her status and you need to file an affidavit of support to show you have certain income to support your mother. You have to start this process and then deal with the problems (i.e. your mom lives here undocumented) as they come.

As a U.S. citizen you can file an immigration relative petition for your mother. However, for your mom to be eligible to file an application for "Adjustment of Status" (Green card) in the United States, she would have to show that there was a petition (either filed by a relative or an employer) on or before April 30, 2001. If your mother doesn't have a prior petition which was filed for her or someone else and she was a derivative beneficiary (for example, if a petition was filed for her parents, etc.), then your mom would have to do "consular processing", which means that she would have to leave the U.S. for her immigrant visa interview (which would be done in Mexico). However, since your mom has been in the U.S. and has more than one year of "illegal presence", she would trigger the 10-year bar to reentry into the U.S., once she leaves the U.S. That is, if she leaves the U.S. she would be barred from reentry into the U.S. for 10 years (as a penalty for being in the U.S. illegally for more than 1 year). Usually, a person can file an application for waiver of the 10-year bar to reentry, if the person can show that the 10-year bar would cause "extreme and unusual" hardship to a "qualifying U.S. citizen or Permanent Resident relative." The qualifying relative under immigration law is a U.S. citizen or resident spouse or parent, but not a child. Since children are not considered "qualifying relatives", so your mom wouldn't be able to file a waiver application based on hardship to you. So at this point you should file the petition for your mom, but because she cannot file an application for Greencard and unless she has a qualifying relative, she cannot file an application for waiver of the 10-year bar, she should wait and see if the Immigration Reform passes. But, make sure she does not leave the U.S. because if she leaves the U.S., she would trigger the 10-year bar and without the waiver, she would not be able to return to the U.S.

If you are a US citizen, you can petition for your mother. If you mother entered the US with a visa you can file the Green Card application along with the petition. If she entered illegally and nobody has filed a petition for before 04/31/2001, then after the petition is approved, she will have to file a waiver for her unlawful presence and then if that is approved she will have to go back to her country and come back with a immigrant visa.

You should file an I-130 visa petition with the supporting documents listed on the instructions. If your mother entered the US with a visa, she can apply for lawful permanent residency at the same time. If she entered without inspection, she should consult an immigration attorney for a more detailed analysis.