• Although common in tropical regions, pyomyositis is rare in the continental United States. Fewer than 50 cases have been reported to date. It is characterized by suppuration of large muscle groups that can, if not quickly and appropriately treated, lead to sepsis and death. Diagnosis can be difficult secondary to the atypical appearance of the abscess process early on. Almost all cases have occurred in otherwise healthy people. The simultaneous occurrence of pyomyositis and immunodeficiency is rare. A recent report of a case in an adult with the acquired immunodeficiency syndrome (AIDS) is not, however, unexpected. We describe the first documented occurrence of pyomyositis in a child with AIDS. A brief review of the topic is included. Pyomyositis should be included in the list of unusual infections that can occur in children with AIDS.