Twelve cases of necrotizing fasciitis were identified retrospectively over a 5-year period. All were associated with a history of substance abuse by injection or with diabetes. Eleven of the 12 infections were associated with beta-hemolytic Streptococcus, a mixed anaerobic aerobic infection, or both. Three of five patients tested for human immunodeficiency virus had positive test results. A wide extensile approach was used to debride necrotic fascia. An average of 3 debridements were necessary, with a range of 1-6 debridements. Two patients under-went shoulder disarticulation because of uncontrollable infection. The rapid and destructive nature of this disease makes early recognition, aggressive debridement, and antibiotic therapy necessary to minimize morbidity.