The author describes the microbiology and clinical features of six pyomyositis infections in children, which yielded anaerobic bacteria. Anaerobic bacteria alone were recovered in four instances, and they are mixed with facultative bacteria in two. There were 15 bacterial isolates (13 anaerobic, 2 facultative). The bacteria were Peptostreptococcus sp (5 isolates), Bacteroides fragilis (3), Clostridium sp (2), Fuso-bacterium nucleatum (1), Prevotella sp (1), Bateroides sp (1), Streptococcus pyogenes (1), and Escherichia coli (1). Recent trauma or injury had occurred in five cases; three such injuries were from penetrating objects. This study highlights the potential importance of anaerobic bacteria in children with pyomyositis.