Information concerning the mammals of Zion National Park was needed for management purposes and general information. During the summers of 1975 and 1976, mammals observed throughout the park were recorded and habitat structure was measured for each animal at the immediate observation site. Ordinations based on stepwise discriminant analyses of the data on 12 rodent species were constructed and substantiated by Bray-Curtis analyses. The results showed that amounts of cover and boulders contrasted the habitats of Peromyscus eremicus, P. maniculatus, P. crinitus, P. boylii and P. truei. A second group of species--Eutamias minimus, E. umbrinus, Spermophilus variegatus, Tamiasciurus hudsonicus, Dipodomys merriami, Neotoma lepida and Microtus longicaudus--were discriminated by amounts of litter, grass and trees in the habitat of each species. A list of mammalian species found within Zion and suggestions for further study are given.