Sixteen knees with hematogenous septic arthritis in 12 adult patients were treated by arthroscopic decompression, debridement, and irrigation with motorized instruments plus suction drainage. Infectious disease consultants supervised the administration of intravenous antibiotics, and range-of-motion exercises were instituted when the drains were removed 48 hours after surgery. Patients were protected from bearing weight for six weeks. There were no treatment complications, and no patient required a repeated drainage procedure. Two patients died of diseases unrelated to knee infection. The 11 infected knees of the ten surviving patients were evaluated subjectively, functionally, objectively, and roentgenographically. With an average 34-month follow-up evaluation, all patients regained their preoperative functional status without loss of motion or roentgenographic evidence of cartilage loss. Arthroscopic debridement of the knee for septic arthritis is a safe, efficient method of joint decompression with minimal morbidity.