Eleven cases (6 adults and 5 pediatrics) of shoulder septic arthritis are described, and the English literature from 1960 to 1997 reviewed, for a total of 168 cases. Shoulder septic arthritis is an uncommon and difficult diagnosis requiring a high index of suspicion and early evaluation of the affected shoulder by the clinician. The disease usually involves very young infants or elderly patients (65-75 years old). Associated medical conditions were identified in 60% of the patients and include systemic disorders such as liver diseases, alcoholism, and malignancies in 46%; preceding chronic arthritic disorders in 24%; and associated infectious focus in 13% of the patients. Associated infections were more prevalent in the pediatric population. Intravenous drug abuse appears not to constitute a major risk factor, it was identified in less than 5% of patients. All patients presented with acute shoulder ache or with exacerbation of existing chronic pain in joints previously damaged. Elevated body temperature (over 38°C) appeared in 67% adult patients and in over 90% of the pediatric patients. Shoulder arthritis was frequently accompanied by an accelerated erythrocyte sedimentation rate that may rise above 100 mm/hr. Increased white blood cell count was found in approximately 40% of patients. The initial X-rays were frequently normal. While ultrasonography supported the diagnosis in some cases by demonstrating accumulation of fluid inside the joint space. Aspiration of synovial fluid from the affected glenohumeral joint was necessary to evaluate the offending pathogen. False-negative Gram stain appeared approximately 90% of the patients, whereas synovial fluid cultures demonstrated the pathogen in 88% of patients. Blood cultures were positive in 50% of adult patients and 90% of pediatric patients. The most common isolated pathogen was Staphylococcus aureus, which accounted for 41% of infections. Gram-negative bacilli, which accounted for about 20% of infections, are more prevalent in the pediatric population, especially the neonates. Pyogenic shoulder arthritis should first be treated with intravenous antibiotics, effective at least against staphylococcal infections, until the organisms and sensitivities are identified. Duration of antibiotic therapy should be 3-6 weeks. Unfortunately, our experience in addition to the literature summary does not allow statistical analysis and firm conclusions concerning the best therapeutic approach. However, it appears that in the adult population an operative draining procedure is preferred, whereas in the pediatric population, a closed needle aspiration, if needed at all, is the optimal treatments. With prompt antibiotic therapy and drainage of the shoulder, the patient can be expected to improve clinically, with no serious long-term debilitating effects from the disease.