I live in Virginia.
My wife and I were separated for most of 2011. (Divorced in December).
I paid approximately $1,000 a month of her bills, including the second mortgage of $500 per month.
She paid the primary mortgage of $2000 per month, AND lived in the house.

Who gets to deduct what, in terms of mortgage interest?

“Who gets to deduct what, in terms of mortgage interest?”---->As long as your name is on the mortgage, you can deduct $18,000;$1,000*12+$500*12 on Sch A of 1040 line 10;if you do NOT itemize your deductions, then you can’t deduct your mortgage interest. If your name is NOT on the mortgage, you can NOT deduct mortgage interest $18,000.As long as her name is on the mortgage, she can deduct $24,000;$2,000*12 on Sch A line 10 as long as he itemizes deductions. If she is co-owner of the home and legally liable on the mortgage, she can deduct the mortgage interest and property tax actually paid by her or paid out of her earnings. If you are in a community property state, the amount she can deduct is usually 50% of the mortgage and property taxes. If her name is on the deed but NOT on the mortgage, then she can’t deduct $24,000 paid by her.

Thank you WnHough.

We are BOTH on the deed, BOTH on the Mortgage, and BOTH on the second mortgage.
She pays first Mortgage of approximately $2000 per month, and lives in the house.
I pay the second mortgage of approximately $500 per month, but also rent an apartment.
I pay R/E taxes of aprroximately $2400 per annum.

She can claim ALL the interest on the $24,000 mortgage that she pays, yet I can still claim half of that interest? Is that correct?
I can claim ALL the interest on the second mortgage, AND the R/E taxes that I paid. Is that correct?

It seems to me that between us, we are claiming 150% of the interest paid on the first mortgage.
Is this correct?
I don't know if Virginia is a communal property state.

“She pays first Mortgage of approximately $2000 per month, and lives in the house.I pay the second mortgage of approximately $500 per month, but also rent an apartment.I pay R/E taxes of aprroximately $2400 per annum.”--->You can deduct mortgage interest on a second home even if you never use it if the second home is not rented out. If you do rent it out, you must PERSONALLY FOR PERSONAL USE use the home for at least 14 days or 10 percent of the time it is rented out, whichever is larger. Your total mortgage debt that you can deduct interest from is limited to $1 million , OR $500,000 if you are married filing separately. For example, if your first home has a mortgage of $400,000 and your second home has a $100,000 mortgage, the entire amount , $500,000 as a MFS filer, would be deductible. Your home mortgage interest is an itemized tax deduction on Schedule A of Form 1040 line 10. There are various conditions and limits that apply to deducting mortgage interest. You must be legally liable for the loan.The mortgage must be a secured debt on a qualified home in which you have an ownership interest. A qualified home is your main home or a second home. So, unless you itemize your deductions on Sch A , you can’t deduct your mortgage interest. Both meet the standards as far as qualifying as a second home and the total mortgaged value. You,UNLESS you are r/e professional or dealer, need to deduct your rental pty r/e taxes on Sch E of 1040 line 16.However, you are subject to a passive activity loss rule; in general, passive activity losses can only offset passive activity income, and passive activity tax credits can only be used against tax attributable to passive activity income on your tax return. Any disallowed passive activity losses and passive activity tax credits are tax deferred until passive activity income is generated or the passive activity is disposed of in a taxable transaction.
“She can claim ALL the interest on the $24,000 mortgage that she pays,”?---->Correct on her SCh A of 1040 onher 2011 return;however, her ability to fully utilize her itemized deductions may be limited if her AGI exceeds the amount determined by the tax code for the previous tax year,2011. You can NOT claim half of that interest paid by her; as said previously, you CAN deduct mortgage interest that you paid.
“yet I can still claim half of that interest? Is that correct?”---->As long as yu paid the interest;if NOT, then you can NOT deduct interest that you didn’t pay. if you are the primary borrower, you are legally obligated to pay the debt and you actually make the payments. If you are married and both you and your spouse sign for the loan, then both of you are primary borrowers. If you pay your son's or daughter's mortgage to help them out, however, you cannot deduct the interest unless you co-signed the loan.
“I can claim ALL the interest on the second mortgage, AND the R/E taxes that I paid. Is that correct?”--->Correct as long as they were paid by YOU, NOT by her.
“It seems to me that between us, we are claiming 150% of the interest paid on the first mortgage.
Is this correct?”--->No you can NEVER claim 150% of the interest paid;
“I don't know if Virginia is a communal property state.”---> The states of the United States that recognize community property are primarily in the West; it was inherited from Mexico's ganancial community system; VA state is NOT a CP state.