For the efficacy and safety of partial stapedectomy, Co2 laser was used in 44 patients with otosclerosis. Postoperative follow-up (3-12 months) demonstrated that the average hearing gain was 31.7 +/- 8.2 dB, and air-bone conduction gap was within 11.2 +/- 6.6 dB. There was no significant hearing change at 4.000 Hz. The advantages of CO2 laser technique are summarized as follows: convenience for cutting posterior crus, less time needed for penetration of thick footplate or removal of occlusive sclerotic plaque in oval window niche, avoidance of footplate floating, rapid coagulation of residual stapedial artery and absence of instrumentation difficulties in narrow spaces. Our results indicate that CO2 laser provides essential benefits in stapedectomy for otosclerosis.