Disseminated infection with the rapidly growing mycobacteria Mycobacterium chelonae and Mycobacterium fortuitum is uncommon. Only eight cases were diagnosed at Duke University Medical Center (Durham, NC) over the last 14 years. We identified 46 other cases by review of the medical literature since 1960. We categorized these 54 cases into three groups according to underlying disease and outcome. Group 1 comprised patients with no identified immune defect, a kidney transplant, collagen vascular disease, or chronic renal failure; these patients usually presented with skin involvement and responded well to antimicrobial therapy (survival rate, 90%). Group 2 comprised patients with cell-mediated immune deficiency, lymphoma, or leukemia; they presented with widespread, multiorgan involvement and severe illness. The survival rate in this group was only 10%. Patients in group 3 (who had other underlying diseases) had intermediately severe illnesses and intermediate responses to therapy. These groups provide the basis for an understanding of disseminated infection secondary to rapidly growing mycobacteria and of the profound effect that unresolved immunosuppression has on survival.