Can I claim my ex-wife as I dependent if we still live together and I support her financially 100 percent? the divorce was final like 5 years ago but she doesn't work to take care of our disable son.

Maybe. You can claim your ex-wife as a dependent if she meets the four tests as a "qualifying relative:" 

1.  Not a qualifying child - Since she is your ex-wife, she meets this test.

2.  Member of household or relationship test – Your ex-wife must live with you all year as a member of your household, since she is no longer legally related to you.

3.  Gross income test - To meet this test, a person's gross income for the year must be less than $4,050.  Gross income is all income in the form of money, property, and services that isn't exempt from tax.

4. Support test - To meet this test, you generally must provide more than half of a person's total support during the calendar year.  You figure whether you have provided more than half of a person's total support by comparing the amount you contributed to that person's support with the entire amount of support that person received from all sources. This includes support the person provided from his or her own funds.

Worksheet 2 in IRS Pub. 501 (p. 16) may be helpful in figuring whether you provided more than half of your ex-wife’s support.

If your ex-wife meets all four tests, you may claim her as a dependent on your return.

Thank you!