We show that two new classes of orthogonal polynomials can be derived by applying two orthogonalization procedures due to Lowdin to a set of monomials. They are new in that they possess novel properties in terms of their inner products with the monomials. Each class comprises sets of orthogonal polynomials that satisfy orthogonality conditions with respect to a weight function on a certain interval. (c) 2005 Wiley Periodicals, Inc.