Is it allowed to put mortgage interest on my tax return for 2nd home that is a rental income property on form 1098 and under expenses under rental income?

[spencerjholt]

My first home that I also own has a mortgage that I will deduct under form 1098.

[KrisD15]

No, 

According to the IRS:

"Second home rented out. If you have a second home and rent it out part of the year, you must also use it as a home during the year for it to be a qualified home. You must use this home more than 14 days or more than 10% of the number of days during the year that the home is rented at a fair rental, whichever is longer. If you don't use the home long enough, it is considered rental property and not a second home. For information on residential rental property, see Pub. 527."

[christine1]

If you add the 1098 form it will ask if it should be linked to an asset.  i.e. your rental. 
There is a field for property taxes. 

So yes, it is "allowed" to put mortgage interest on a rental.

[AnnetteB6]

The key point here is that the mortgage interest for a second home that is also rented cannot be claimed in full as both an itemized deduction and a rental expense.

The mortgage interest must be prorated between the time that the property was rented and the time that it was used personally.  The rental portion of the mortgage interest is claimed on Schedule E as a rental expense.  The personal portion of the mortgage interest is claimed on Schedule A as a deduction.  The total of both of these amount cannot exceed the total mortgage interest paid for the second home.

Using TurboTax to enter this information, the Schedule E is typically covered first and the personal portion of the second home/rental home mortgage interest may be automatically included on Schedule A.  However, this should be verified on screen as the Schedule A deductions are completed.

@christine1 

@spencerjholt