Approximately 60% of deaths in patients with AIDS are a direct result of infection other than HIV. The more severe and life-threatening complications of HIV infection occur in patients with a CD4(+) T cell count <200 cells/μL. In the absence of effective retroviral therapy, these infections are associated with a high mortality. We describe a case of disseminated toxoplasmosis discovered at autopsy in a patient with undiagnosed AIDS.