An adult mountain lion (Felis concolor) from the vicinity of Weldon, California (USA) was necropsied following euthanasia due to emaciation and proximity to semi-rural housing. There were spherules consistent with Coccidioides immitis within peritoneal surfaces with granulomatous inflammation and fungi consistent with C. immitis were cultured from abdominal fluid. This is the first reported case of coccidioidomycosis in a wild mountain lion.