Objectives: The aim of the study was to find out the reasons of the recurrent or persisting hearing loss after previous stapes surgery indicated for otosclerosis.Background: Revision stapes surgery is a relatively safe surgical method. Recurrent or persisting conductive hearing loss is commonly caused by prosthesis dislocation and adhesions in the oval window. Hearing loss is directly proportional to the number of previous operations. Method: Retrospective analysis of 48 patients after revision stapes surgery was done over a period of 4 years (2005-2008). Improvement of the hearing and the reasons of a previous surgery failure were studied.Results: Results were compared to the other studies. The main reason of the failed surgery was adhesions and dislocation of the prosthesis. The mean postoperative air-bone gap was 12.0 dB. A mean postoperative air-bone gap closure within 10 dB occurred in 24 cases (55.8 %), between 11-20 dB occurred in 11 cases (25.6 %) and above 20 dB in 8 cases (18.6 %). The original prosthesis was replaced with a new one in 41 (95.3 %) cases. In 2 cases (4.7 %), previous prostheses were left in place and fixed by a ionomer glass cement to the long process of incus.Conclusion: Revision stapes surgery is a relatively safe surgical procedure allowing to improve hearing. The number of previous stapes surgery deteriorates hearing (p < 0.05) (Tab. 4, Ref. 20). Keywords: revision stapes surgery, otosclerosis.