Twenty-one patients with severe coccidioidomycosis, including eight with osseous lesions, were admitted to the University of California, Davis, Medical Center, during a recent epidemic. Transient mild ionized hypercalcemia occurred in only two patients, and a tendency toward low normal ionized calciums was noted. Parathyroid hormone levels appeared to be appropriate for the ionized calcium in these patients. There were no significant differences in ionized calcium levels of parathyroid hormone levels among patients with and without osseous coccidioidomycosis. We conclude that hypercalcemia is rare in coccidioidomycosis, even with extensive bony involvement. (Am J Med Sci 1981; 281(2):97–99.)