Pyomyositis is common in the tropics but rarely reported in temperate climates. This disease may give rise to obscure, non-specific, or misleading signs and symptoms. Delayed diagnosis and treatment may lead to death. The most common pathogen is Staphylococcus aureus. We analyzed 8 cases treated in the Tri-Service General Hospital between 1989 and 2001. There were 3 males and 5 females with age ranging from 2 to 66 years. Fever was found in all patients. The mean time lag between the onset of minor symptoms and diagnosis was 10 days. The imaging tools used included sonography, gallium-67 scan, computed tomography, and magnetic resonance imaging. Early application of sonography to any suspected lesions can help to establish diagnosis. All 8 patients recovered smoothly without complications after incision, drainage, and administration of adequate antibiotics for 2 to 4 weeks.