Your parents' income will probably not count if they are outside the US. You can petition for your parents but if your income is insufficient, you will need to get a joint sponsor to sign the affidavit of support on their behalf. You will still need to provide your tax returns and sign the affidavit of support since, as the petitioner, you are also a sponsor. However, if your income is not sufficient, a joint sponsor or sponsors will be required. Additionally, if your parents are in the US, the only way they will be eligible to adjust status is if they entered the US lawfully and can document that lawful entry.
Answered on Mar 21st, 2012 at 2:05 PM