Just because your parents or someone else can claim you as a dependent does not necessarily mean that you do not have to file a tax return. That determination is based on your earned and unearned income during the year, your marital status, any tax withholdings, any tax credits your received and special taxes that you owe, etc. Also, if in 2009 someone else claims you as a dependent, or is entitled to claim you as a dependent, you may not claim a personal exemption for yourself on any tax return filed by you for 2009.
The amount allowed in 2009 for each personal and dependency exemption is $3,650, assuming your adjusted gross income does not exceed certain amounts for your filing status.
Even though your spouse does not work, your spouse is not a dependent according to the Internal Revenue Service. Consequently, you are only allowed to take one personal exemption for your spouse: that is, you cannot claim an additional exemption for your spouse as a dependent.
Generally, for someone to be claimed as a dependent, the individual cannot be married, must be a U.S. citizen, resident alien, or national, or a resident of Mexico or Canada.
The tax requirements regarding dependents, exemptions, and filing status are very complicated. Consequently, you are advised to seek assistance from a tax professional if you have any questions.