We s h o w that the graph isomorphism problem is low for PP and for C = P, i.e., it does not provide a PP or C = P computation with any additional power when used as an oracle. Furthermore, we s h o w that graph isomorphism belongs to the class LWPP (see Fenner, Fortnow, Kurtz 12]). A similar result holds for the (apparently more di cult) problem Group Factorization. The problem of determining whether a given graph has a nontrivial automorphism, Graph Automorphism, is shown to be in SPP, and is therefore low f o r P P , C = P, and Mod k P, k 2.