Small mammals have been proposed as important dispersers of the spores of arbuscular mycorrhizal fungi (AMF), yet few data exist to support this hypothesis. We experimentally tested 2 models of small-mammal dispersal of AMF spores by quantifying their impact on the mycorrhizal inoculum potential of sterile soil flats in a northeast mesophytic forest in Maryland. Epizoochory did not provide a mechanism for spore dispersal in our study. However, our data demonstrated that endozoochory by several small-mammal species can be an effective dispersal mode for AMF. In the field experiment, inoculum potential of soil from plots that were accessible to Peromyscus leucopus (White-footed Mouse) was significantly higher than in control plots, which excluded small mammals. This study provides experimental evidence that White-footed Mice disperse AMF spores.