A patient had progressive disseminated coccidioidomycosis and depressed cellular immunity to Coccidioides immitis. He developed a large nasal coccidioidal lesion that was unresponsive to conventional therapy. Application of dinitrochlorobenzene (DNCB) to the nasal lesion was temporally associated with resolution of the lesion and stabilization of the systemic disease. In addition, DNCB application was followed by signs of cellular immunity to C. immitis. These included development of delayed cutaneous hypersensitivity to coccidioidin, as well as lymphokine production and lymphoproliferative responses to coccidioidin. Similar forms of DNCB immunotherapy may prove useful in other patients with fungal disease and depressed cellular immunity.