Check only the filing status that applies to you. The ones that will usually give you the lowest tax are listed last.

• Married filing separately.
• Single.
• Head of household.
• Married filing jointly or qualifying widow(er) with dependent child.

You can check the box on line 1 if any of the following was true on December 31, 2010.

• You were never married.
• You were legally separated according to your state law under a decree of divorce or separate maintenance. But if, at the end of 2010, your divorce was not final (an interlocutory decree), you are considered married and cannot check the box on line 1.
• You were widowed before January 1, 2010, and did not remarry before the end of 2010. But, if you have a dependent child, you may be able to use the qualifying widow(er) filing status. See the instructions for line 5 that begin on page 14.

You can check the box on line 2 if any of the following apply.

• You were married at the end of 2010, even if you did not live with your spouse at the end of 2010.
• Your spouse died in 2010 and you did not remarry in 2010.
• You were married at the end of 2010, and your spouse died in 2011 before filing a 2010 return.

For federal tax purposes, a marriage means only a legal union between a man and a woman as husband and wife. A husband and wife filing jointly report their combined income and deduct their combined allowable expenses on one return. They can file a joint return even if only one had income or if they did not live together all year. However, both persons must sign the return. Once you file a joint return, you cannot choose to file separate returns for that year after the due date of the return.

If you file a joint return, both you and your spouse are generally responsible for the tax and any interest or penalties due on the return. This means that if one spouse does not pay the tax due, the other may have to. However, see Innocent spouse relief on page 75.

Generally, a husband and wife cannot file a joint return if either spouse is a nonresident alien at any time during the year. However, if you were a nonresident alien or a dual-status alien and were married to a U.S. citizen or resident alien at the end of 2010, you may elect to be treated as a resident alien and file a joint return. See Pub. 519 for details.

If you are married and file a separate return, you will usually pay more tax than if you use another filing status for which you qualify. Also, if you file a separate return, you cannot take the student loan interest deduction, the tuition and fees deduction, the education credits, or the earned income credit. You also cannot take the standard deduction if your spouse itemizes deductions.

Generally, you report only your own income, exemptions, deductions, and credits. Different rules apply to people in community property states. See page 20.

Be sure to enter your spouse's SSN or ITIN on Form 1040A unless your spouse does not have and is not required to have an SSN or ITIN.

This filing status is for unmarried individuals who provide a home for certain other persons. You are considered unmarried for this purpose if any of the following applies.

• You were legally separated according to your state law under a decree of divorce or separate maintenance at the end of 2010. But, if at the end of 2010, your divorce was not final (an interlocutory decree), you are considered married.
• You are married but lived apart from your spouse for the last 6 months of 2010 and you meet the other rules under Married persons who live apart on this page.
• You are married to a nonresident alien at any time during the year and you do not choose to treat him or her as a resident alien.

Check the box on line 4 only if you are unmarried (or considered unmarried) and either Test 1 or Test 2 applies.

You paid over half the cost of keeping up a home that was the main home for all of 2010 of your parent whom you can claim as a dependent, except under a multiple support agreement (see page 18). Your parent did not have to live with you.

You paid over half the cost of keeping up a home in which you lived and in which one of the following also lived for more than half of the year (if half or less, see Exception to time lived with you on this page).

1. Any person whom you can claim as a dependent. But do not include:
   1. Your qualifying child whom you claim as your dependent because of the rule for Children of divorced or separated parents that begins on page 17,
   2. Any person who is your dependent only because he or she lived with you for all of 2010, or
   3. Any person you claimed as a dependent under a multiple support agreement. See page 18.
2. Your unmarried qualifying child who is not your dependent.
3. Your married qualifying child who is not your dependent only because you can be claimed as a dependent on someone else's 2010 return.
4. Your child who, even though you are the custodial parent, is neither your dependent nor your qualifying child because of the rule for Children of divorced or separated parents that begins on page 17.

If the child is not your dependent, enter the child's name on line 4. If you do not enter the name, it will take us longer to process your return.

To find out if someone is your qualifying child, see Step 1 on page 16.

To find out if someone is your dependent, see the instructions for line 6c that begin on page 16.

Temporary absences by you or the other person for special circumstances, such as school, vacation, business, medical care, military service, or detention in a juvenile facility, count as time lived in the home. Also see Kidnapped child on page 18, if applicable.

If the person for whom you kept up a home was born or died in 2010, you can still file as head of household as long as the home was that person's main home for the part of the year he or she was alive.

To find out what is included in the cost of keeping up a home, see Pub. 501.

If you used payments you received under Temporary Assistance for Needy Families (TANF) or other public assistance programs to pay part of the cost of keeping up your home, you cannot count them as money you paid. However, you must include them in the total cost of keeping up your home to figure if you paid over half the cost.

Even if you were not divorced or legally separated at the end of 2010, you are considered unmarried if all of the following apply.

• You lived apart from your spouse for the last 6 months of 2010. Temporary absences for special circumstances, such as for business, medical care, school, or military service, count as time lived in the home.
• You file a separate return from your spouse.
• You paid over half the cost of keeping up your home for 2010.
• Your home was the main home of your child, stepchild, or foster child for more than half of 2010 (if half or less, see Exception to time lived with you above).
• You can claim this child as your dependent or could claim the child except that the child's other parent can claim him or her under the rule for Children of divorced or separated parents that begins on page 17.

An adopted child is always treated as your own child. An adopted child includes a child lawfully placed with you for legal adoption.

A foster child is any child placed with you by an authorized placement agency or by judgment, decree, or other order of any court of competent jurisdiction.

You can check the box on line 5 and use joint return tax rates for 2010 if all of the following apply.

• Your spouse died in 2008 or 2009 and you did not remarry before the end of 2010.
• You have a child or stepchild whom you claim as a dependent. This does not include a foster child.
• This child lived in your home for all of 2010. If the child did not live with you for the required time, see Exception to time lived with you below.
• You paid over half the cost of keeping up your home.
• You could have filed a joint return with your spouse the year he or she died, even if you did not actually do so.

If your spouse died in 2010, you cannot file as qualifying widow(er) with dependent child. Instead, see the instructions for line 2 that begin on page 13.

An adopted child is always treated as your own child. An adopted child includes a child lawfully placed with you for legal adoption.

To find out if someone is your dependent, see the instructions for line 6c that begin on page 16.

Temporary absences by you or the child for special circumstances, such as school, vacation, business, medical care, military service, or detention in a juvenile facility, count as time lived in the home. Also see Kidnapped child on page 18, if applicable.

A child is considered to have lived with you for all of 2010 if the child was born or died in 2010 and your home was the child's home for the entire time he or she was alive.

To find out what is included in the cost of keeping up a home, see Pub. 501.

If you used payments you received under Temporary Assistance for Needy Families (TANF) or other public assistance programs to pay part of the cost of keeping up your home, you cannot count them as money you paid. However, you must include them in the total cost of keeping up your home to figure if you paid over half the cost.