The Internal Revenue Service (IRS) has delineated five criteria that must be met, however, before you may do so as a single filer; the requirements are as follows:
1. Your partner’s citizenship/residency.
Your partner must be a citizen or resident alien of the United States or a citizen of Mexico or Canada. Also, he or she must have lived with you for the entire taxable year.
2. The financial support you provided.
You must have provided at least half of your partner’s financial support for the year; this includes all kinds of expenses, including food, housing, education, medical care, clothing, etc.
3. Your partner’s taxable income.
Your partner’s taxable income cannot be over a certain amount for the year; this amount changes yearly, so be sure to check with the IRS or a tax professional for current, accurate information. Note that nontaxable Social Security benefits and welfare benefits are not included in gross income.
4. Your relationship with your partner.
The IRS requires that your relationship with your claimed dependent not be in violation of state law. Remember that in some states, sodomy, cohabitation, and other such laws may still be in effect. Some tax attorneys may advise you to go ahead and claim your partner as your dependent anyway if you satisfy the other requirements; be sure to consult a tax attorney or other tax professional if you fall into this category, though.
5. Your partner’s marital status.
If your partner is married and files a joint tax return with his or her spouse, you cannot claim your partner as a dependent *unless* your partner and his/her spouse filed taxes only to receive a refund; in that case, you may claim your partner as a dependent if you meet all the other requirements.