Of 49 deer (Odocoileus hemionus columbianus) sampled from several California herds, from 0 to 57 percent of animals per herd were infected with cysts of Echinococcus granulosus. The highest prevalence rates were in deer from areas in which livestock are absent and coincided in one instance with an area in which approximately 20 percent of coyotes had been found infected with the adult parasite. It is probable that transmission of E. granulosus between coyotes and deer takes place, at least locally, in California.