Infection of the thyroid gland with Coccidioides immitis, the causative agent of coccidioidomycosis, is very rarely recognized antemortem. We report 2 recent cases, one immunosuppressed by corticosteroid treatment of sarcoidosis and the other without any recognized impairment of host defenses. In the first case, thyroid gland involvement was but 1 indication of disseminated infection. In the second case, the patient appeared to have autoimmune thyrotoxicosis without clinical evidence of coccidioidomycosis elsewhere. Although historical autopsy studies have indicated that coccidioidal involvement of the thyroid gland can infrequently occur as part of fatal disseminated infection, to our knowledge only 2 other cases of infection detected during life have been reported. Optimal treatment of this rare complication of coccidioidomycosis is uncertain.