An unusual case of primary osteomyelitis of the acetabulum caused by Aspergillus flavus in a presumed immunocompetent adult is presented. Review of the literature found 25 additional cases of aspergillar osteomyelitis, which occurred predominantly in hosts with either inborn or acquired immune defects. There were notable differences between the adult and the pediatric cases in causation, clinical presentation, and treatment regimens. In children, the underlying cause was usually severe immunocompromise; among adults, the majority of cases occurred in hosts presumed to be immunocompetent. In all but one case, the children were treated with antifungal chemotherapy alone, whereas the adult patients nearly always received surgical debridement in conjunction with chemotherapy.