목적: The primary objective of this study is to estimate the success rate of stapes surgery in patients with otosclerosis in a tertiary care hospital. The secondary objective is to find the factors affecting the outcomes and to evaluate the prevalence of postoperative complications. 방법:This is a retrospective study from the electronic medical records of patients with otosclerosis who underwent stapes surgery between Jan 2015 to Dec 2021. The demographic data, operative findings, complications, and pre-and post-operative audiometry were collected. The patients were followed up for at least 1 year. The successful outcome was defined as the postoperative air-bone gap of 10 dB or less without sensorineural hearing loss. The audiometric outcomes and the affecting factors were analyzed using t-test and chi-square test. Multivariate analysis was performed. P- value < 0.05 was considered statistically significant. 결과:Of 175 operated ears, there were 11(6.3%) and 36(20.6%) operated ears underwent revision surgery and loss to follow-up respectively. After the operation. the air-conduction thresholds were improved in almost all frequencies while the bone-conduction thresholds were improved in some frequencies. The air pure tone average, average air-bone gap, and speech reception threshold were significantly decreased. The success rates at short-term and long-term periods were 106/164(64.6%) and 96/128(75.0%). The multivariate analysis showed that the factors associated with successful results included the air pure tone average of 65 dB or less (OR=2.2, p-value=0.05), the average air-bone gap of 35 dB or less (OR=3.8, p-value <0.001), the right side(OR=2.1, p-value=0.039), and body mass index of less than 25.0 kg/m² (OR=2.4, p-value=0.014). The complications were sensorineural hearing loss(11%), TM perforation(2.4%), and taste disturbance(39.0%). 결론:The success rates of stapes surgery were 64.6% and 75.0% at short-term and long-term postoperation. The affecting factors were initial hearing thresholds, air-bone gap, side, and body mass index.