In many cases the surfaces of geometric models consist of a large number of triangles. Several algorithms were developed to reduce the number of triangles required to approximate such objects. Algorithms that measure the deviation between the approximated object and the original object are only available for special cases. In this paper we use the Hausdorff distance between the original and the simplified meshas a geometrically meaningfulerror valuewhich can be applied to arbitrary triangle meshes. We present a new algorithm to reduce the number of triangles of a mesh without exceeding a user-defined Hausdorff distance between the original and simplified mesh. As this distance is parameterization-independent, its use as error measure is superior to the use of the