Abstract. This paper defines mixed multiplicity systems; the Euler-Poincaré characteristic and the mixed multiplicity symbol of N d -graded modules with respect to a mixed multiplicity system, and proves that the Euler-Poincaré characteristic and the mixed multiplicity symbol of any mixed multiplicity system of the type (k 1 , . . . , k d ) and the (k 1 , . . . , k d )-difference of the Hilbert polynomial are the same. As an application, we obtain results for mixed multiplicities.