Objective: To assess long-term hearing outcomes following stapedectomy using a self-crimping shape memory nitinol prosthesis. The results were compared with those of a group of patients who received a conventional prosthesis. Study Design: Retrospective case review. Setting: Tertiary referral center. Patients: All patients who underwent stapedectomy for otosclerosis between July 2001 and November 2008 with a minimum dataset of preoperative, early postoperative (= 6 yr) audiometry were included. Fifty-six patients with a nitinol prosthesis and 27 patients with a titanium prosthesis met the inclusion criteria. Intervention: Stapedectomy using a nitinol or conventional prosthesis. Main Outcome Measure(s): Hearing outcomes by audiological assessment. Results: Mean duration of follow up was 9.5 (standard deviation [SD] 1.4) years in the nitinol group and 12.6 (SD 2.1) years in the titanium group. The early and late mean postoperative air-bone gaps (ABGs) were 9.7 and 9.8 dB in the nitinol group and 11.0 and 12.6 dB in the titanium group, respectively. The proportion of patients achieving an ABG less than or equal to 20 dB at early and late follow up was 96% and 96% in the nitinol group and 92% and 86% in the titanium group respectively. Conclusions: The excellent closure of the ABG achieved at early follow up remains remarkably stable up to 12 years using a self-crimping shape memory nitinol prosthesis. There is no evidence that firm fixation of the hook around the long process of incus has a detrimental effect in the long-term.