Many forms of hypogeous fungi rely on small mammals to consume and disperse their spores. It is well documented in the Pacific Northwest that northern flying squirrels (Glaucomys sabrinus) rely on hypogeous fungi as a food resource. However, in more northern forests the taxonomic constituents of flying squirrel diets are relatively poorly documented. Using live-capture to obtain fecal samples, I examined dietary fungal diversity from the feces of 44 northern flying squirrels inhabiting variable-aged managed forest stands during late summer in the foothills of west-central Alberta, Canada. Fungal material was found in all specimens, and was identified to order, family, or genera via microscopic spore morphological classification. Twenty-six spore morphologies were found; 1 was identified to order, 4 to family, 13 to genus, and 8 remained unidentified. The most frequently consumed fungi were of the hypogeous form of the genera Cortinarius, Gastroboletus, and Hysterangium. Insect material also figured prominently. In contrast to epigeous-dominated winter diets of flying squirrels found elsewhere in Alberta, here, hypogeous species formed almost one-half of those identified. There is evidently notable consistency in species richness of fungi in flying squirrel diets continent-wide but in more northern forests, diets may shift from epigeous species during winter months to hypogeous species in summer.