A review of adults with septic arthritis was undertaken to evaluate outcome of treatment and intensive care requirements in a community-based teaching hospital. During an 80-month period (1986-1992), 38 cases of septic arthritis were identified. Underlying joint disease was present in 84% of patients. Mean age was 68 years, with a range of 26 to 100 years and a median of 70 years. Patients did not always initially display signs of infection; fever was present in only 42%, and leukocytosis was present in 67%. Total in-hospital mortality was 26%, but the mortality attributed to septic arthritis was 13%. Polyarticular septic arthritis occurred in 26% of patients and carried a 40% mortality. Twenty-four percent of patients required transfer to the intensive care unit (ICU); they had a 67% mortality. Three of four patients with polyarticular septic arthritis requiring intensive care died. Average length of hospital stay for survivors receiving a full course of antibiotics was 35 days; it diminished to 14 days for 5 uncomplicated cases who received home IV antibiotics. Eighty-nine percent of survivors had return of function of the affected joints. Thirty-two percent required surgical intervention, and 5% were complicated by osteomyelitis. Septic arthritis remains a costly disease affecting primarily the elderly with underlying joint disease. Polyarticular septic arthritis and the need for ICU care portend a high mortality. The functional outcome of those who recovered was generally good.