My sister and I have a Home Equity Loan on a house her, my brother and I own together. Which one of us claims the interest and real estate taxes?

[Opus 17]

If you are both borrowers on the loan, and both owners of the house, then you divide the interest and taxes based on who paid what.  50/50, 60/40, or whatever. 

[ThomasM125]

Any of you can deduct the portion of the mortgage interest and property taxes you paid on your personal return as an itemized deduction,  provided you are legally obligated to pay the loan or property taxes. This is assuming the house is your primary residence or it is a second home of yours. If the house is rented out, you can deduct your portion of the expenses against your portion of the rental income.