Adults and adolescents diagnosed with AIDS from 1987 through 1992 residing in counties endemic (selected counties in California, Arizona, Texas, New Mexico, Nevada, Utah) and not endemic for Coccidioides immitis were assessed to determine the frequency of and risk factors for disseminated coccidioidomycosis. Of 602 AIDS patients reported with disseminated coccidioidomycosis, 323 (1.1% of AIDS patients) resided in C. immitis-endemic counties and 279 (0.1% of AIDS patients) resided in C. immitis-nonendemic counties in 35 states. In multivariate analysis, patients with disseminated coccidioidomycosis in C. immitis-endemic counties were more likely to be injecting drug users (odds ratio, 2.6; 95% confidence interval, 1.8-3.7) and blood product recipients (odds ratio, 3.6; 95% confidence interval, 1.5-8.3) than to be homosexual or bisexual men. Of patients with disseminated coccidioidomycosis, 63% had died by 1 year after AIDS diagnosis. Disseminated coccidioidomycosis should be considered in AIDS patients in all areas of the United States.