Mortgage cost are added to the basis of your property. When you refinanced the original fees that were added to your basis do not change. The basis in your property will be used when you sell the property to determine any gain or loss on the sale.
The costs associated with obtaining a mortgage on rental property are amortized (spread out) over the life of the loan. For example, if it cost you $3,000 to refinance your 30-year mortgage, you'd be able to deduct $100 per year for the next 30 years.
