maybe. First, you're limited to having just one second home at a time for the purposes of the mortgage interest deduction. For example, if you're already deducting interest on a mortgage for a home that isn't your primary residence, you can't deduct the interest on your timeshare. Second, the mortgage interest deduction can be limited based on when each of your original mortgages was taken out or if you refi'd a mortgage for more than the balance at the time of the refi.
the Timeshare must be deeded and recorded in public records and it meets all the requirements for deducting mortgage interest. if you rent it out during the period you have a right to use it certain other rules apply
was personal use more than the greater of (a) 14 days or (b) 10% of days rented?
if no, rental less prorated rental expenses go on schedule E. the personal portion of mortgage interest is not deductible
if yes, was property rented less than 15 days?
if yes, it's deemed a personal residence - rental income and expense are not reported
if no, prorate expenses. rental income and the pro rata portion of taxes and interest are deductible on Schedule E. other pro rata expenses are limited to remaining I from the property and are subject to ordering rules. carryovers are allowed
