Lungs from three species of ground squirrels collected in south central Saskatchewan were examined by histopathology and a digestion technique for adiaspores of Emmonsia crescens. Two of 81 (2.5%) Citellus richardsoni, 3 of 17 (17.6%) C. tridecemlineatus and 35 of 44 (79.5%) C. franklini were infected. Infection was more common in adults than in young-of-the-year. Tissue digestion was the more sensitive method for detecting adiaspores. Possible reasons for the difference in prevalence among the species are discussed.