Twenty-one patients older than 60 years of age with septic arthritis were reviewed over a ten-year period. The knee was the joint most commonly involved. Concurrent medical illnesses were noted in the majority of patients, with diabetes mellitus present in 24%. Seventy-one percent of patients had roentgenographic evidence of preexisting joint disease in the affected joint. Most patients were afebrile and had normal white blood cell counts at the time of admission. The erythrocyte sedimentation rate was elevated in all patients tested, with an average value of 79. Despite surgical treatment in the majority of patients, the complication rate was high, with 38% developing osteomyelitis; 14%, secondary osteoarthritis; and 19%, mortality due to sepsis. Septic arthritis in the elderly is difficult to diagnose and carries a poor prognosis despite aggressive management.