Objectives: We evaluated 13 patients who were treated and followed-up for synovial chondromatosis.Patients and methods: Thirteen patients (7 females, 6 males; mean age 41 years; range 16 to 68 years) had synovial chondromatosis localized in the knee (n=8), hip (n=3), shoulder (n=1), and subtalar joint in the foot (n=1). Diagnoses were made by radiologic assessment in 10 patients, by arthroscopic evaluation in two patients, and by excisional biopsy and histopathologic evaluation in one patient with subtalar joint involvement. Three patients refused surgical treatment and were treated conservatively. Joint loose bodies were removed together with synovectomy by open surgery in eight patients and by arthroscopic treatment in two patients. Histopathologic confirmation was obtained in all the patients. The mean follow-up period was six years (range 1 to 9 years).Results: One patient developed recurrence eight months after open surgery, for which repeat synovectomy was performed in the knee. No other recurrences were observed. Symptomatic improvement was obtained in all the patients treated surgically, without any signs of degeneration in the affected joints. However, three patients treated conservatively developed mild to severe degeneration. Of these, two patients with involvement of the knee and hip, respectively, had increased pain and limitation of movements. The latter required total hip arthroplasty in the fifth year of follow-up. The remaining patient with shoulder involvement had no limited range of motion, but had pain of less intensity and frequency. However, joint loose bodies in this patient increased in both number and size, accompanied by mild degenerative changes in articular surfaces.Conclusion: Surgical treatment is essential in synovial chondromatosis and patients must be followed-up with regard to recurrence.