Sixteen patients (average age, 38 years; range, 20-63 years) with pyarthrosis were treated during a ten-year period by arthroscopic techniques consisting of joint debridement and application of suction drains, combined with appropriate antibiotics. There were 13 knees, two shoulders, and one ankle in the series. At the first visit to the authors' institution, patients typically had fever, leukocytosis, elevated sedimentation rate, and localized joint findings, such as generalized tenderness, swelling, effusion, and painful, limited range of motion in almost every joint involved. Most patients were seen two to five days after the onset of symptoms. After the initial culture and sensitivity were obtained and broad-spectrum antibiotics were administered, all patients were taken to the operating room on an emergency basis. At an average follow-up evaluation of 36 months (range, 14-48 months), the results have been excellent to good, without evidence of recurrence.