A case of primary synovial chondromatosis of the shoulder in a 15-year-old girl is presented. Plain radiographs revealed findings characteristic of synovial chondromatosis. The patient was treated by arthroscopic loose body removal and arthroscopic partial synovectomy of the glenohumeral joint. Although immediate postoperative radiographs showed no calcification in the joint, repeated radiographs at 18 months after surgery revealed recurrence of calcification in the subacromial space. Arthroscopic removal of all loose bodies and partial synovectomy appears to be a good method of giving symptomatic relief and early return to work. However, late recurrence should be anticipated.