Synoviorthesis is the intra-articular injection of chemical or radioactive substances able to produce fibrosis of hypertrophied synovium, which has proved effective in the treatment of chronic haemophilic synovitis. Between September 1999 and October 2001 we treated 28 outpatients (25 with haemophilia A, three with haemophilia B). Our treatment was focused on pain and functional limitation of joints. A schedule was adopted to treat each joint using intra-articular rifamycin once a week, repeated five times. Patients were covered with factor replacement on demand. Oral analgesia was offered as required because of acute but transient painful inflammatory reaction. Their median age was 34 years (range 15-60 years). The indication for synoviorthesis was chronic synovitis characterized by recurrent haemarthroses, persistent pain and limited range of motion (ROM). Thirty-five joints were treated with a total of 169 injections, including six joints (20%) in patients with inhibitors. In five patients two joints were treated in the same session. Thirty procedures were completed: 24 (80%) were considered effective (as excellent or good), while six were considered insufficient (20%). Pain was reduced in 96% of cases and in 70% the ROM was improved. In our experience intra-articular infiltration with rifamycin appears to be effective in reducing joint pain and in improving the ROM. The procedure presents a low risk of bleeding, can be used for patients with inhibitors and multiple joints can be treated without any additional cost.