Coccidioidomycosis is a fungal infection caused by inhalation of airborne Coccidioides immitis spores that are present in the arid soil of the southwestern United States, California, and parts of Central and South America. Infection with C. immitis previously has not been diagnosed in patients outside these areas, except in travelers returning from areas where the disease is endemic. This report describes an outbreak of coccidioidomycosis in workers at an archeologic site in northeastern Utah during June-July, 2001, and represents the first identification of coccidioidomycosis in northern Utah. Health-care providers should consider coccidioidomycosis in the differential diagnosis for patients with compatible illness who reside in or recently have traveled to this area. Interventions to minimize soil disturbance and dust inhalation can reduce the risk for coccidioidomycosis.