Pyomyositis is a purulent skeletal muscle infection that arises from hematogenous spread, and is usually accompanied by abscess formation. This condition is commonly seen in the tropics, but has recently been recognized in temperate regions. We report a case of pectoralis pyomyositis in an elderly Japanese woman without any serious underlying medical conditions. The course of illness in this case differed from that seen in tropical cases. We should consider pyomyositis as an important complication of bacteremia, particularly because this pathology is no longer limited to tropical regions and clinically ill patients.