X0101 EFFECT 33 LIVE 2007-04-03 16:00:00

N-14

0000746458 AMERICAN CENTURY MUNICIPAL TRUST 333-140914 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006472 TAX-FREE BOND FUND C000017689 INVESTOR CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006469 ARIZONA MUNICIPAL BOND FUND C000017677 INVESTOR CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006472 TAX-FREE BOND FUND C000017689 INVESTOR CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006469 ARIZONA MUNICIPAL BOND FUND C000017678 A CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006472 TAX-FREE BOND FUND C000017689 INVESTOR CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006469 ARIZONA MUNICIPAL BOND FUND C000017679 B CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006472 TAX-FREE BOND FUND C000017689 INVESTOR CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006469 ARIZONA MUNICIPAL BOND FUND C000017680 C CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006472 TAX-FREE BOND FUND C000017689 INVESTOR CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006470 FLORIDA MUNICIPAL BOND FUND C000017681 INVESTOR CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006472 TAX-FREE BOND FUND C000017689 INVESTOR CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006470 FLORIDA MUNICIPAL BOND FUND C000017682 A CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006472 TAX-FREE BOND FUND C000017689 INVESTOR CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006470 FLORIDA MUNICIPAL BOND FUND C000017683 B CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006472 TAX-FREE BOND FUND C000017689 INVESTOR CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006470 FLORIDA MUNICIPAL BOND FUND C000017684 C CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006472 TAX-FREE BOND FUND C000017689 INVESTOR CLASS 0000746458 AMERICAN CENTURY MUNICIPAL TRUST S000006472 TAX-FREE BOND FUND C000017690 ADVISOR CLASS