An undescribed species of Demodex (Acari: Demodecidae) was observed in hair follicles and ducts of sebaceous glands in the ear canals of seven California ground squirrels (Spermophilus beecheyi) from Santa Clara Count); California (USA). The animals had died of unrelated causes and were submitted for necropsy between September 1994 and February 1996. Similar mites were observed in the lumens of hair follicles and ducts of Meibomian glands in the eyelids of two of these squirrels. Microscopic changes in the epithelium and surrounding dermis, when present, were minimal. No associated clinical signs of disease or macroscopic lesions were observed. To our knowledge, this is the first report of Demodex sp. in a ground squirrel.