Charts of 126 patients with coccidioidomycosis were reviewed. Sixteen of these were patients who had malignancies, uremia, or a collagen-vascular disease and/or had received recent immunosuppressive drug therapy. The rate of disseminated infection was 50% in this group. (The dissemination rate was 14% in 110 control patients.) No case of dissemination occurred in patients who only had the above underlying diseases; all cases of dissemination were among those who had received immunosuppressive therapy. The dissemination rate in control patients was higher for patients age 40 or over than for younger patients. The dissemination rate showed no age-related difference, however, in patients treated with immunosuppressive drugs. The dissemination rate was similar in control patients of both sexes and uniformly higher for both immunosuppressively treated males and females. The dissemination rate did not appear to be influenced by the number of circulating lymphocytes if the patient had received immunosuppressive drugs. Patients with disseminated disease who had received immunosuppressive drugs were capable of producing a serological response to the coccidoiidal organism in high titer but none had positive skin test reactivity. Disseminated coccidioidomycosis is not uniformly fatal in the immunosuppressed host: half of our patients are alive an average of 33 months after diagnosis.