40-50%-approximately 43% of homeowners take the mortgage interest deduction.in 2007 there were 75.6 million owner occupied homes. owner occupied homes were 68% of all households. only 29% of tax filers itemized and took the mortgage interest deduction. 26.7 million (35%) of homeowners have no mortgage. 48.9 million (65% of homeowners) have mortgages. 42% of homeowners have mortages and take the mortgage interest deduction. sources: number of owner-occupied homes, 2007 american housing survey table 1a. number of owner-occupied homes with and without mortgages, 2007 american housing survey table 2-19. portion of tax returns with mortgage interest deduction from irs publication 1304 (2006), tables 1.1 and 2.1. note that many people who take the mortgage interest deduction dont get to deduct the full interest cost. if you have no other deductions, the first $11,400 of mortgage interest doesnt exceed the standard deduction.