PURPOSE: Transcatheter aortic valve replacement (TAVR) has emerged as a therapeutic option for severe aortic valvular stenosis (AS). To determine the indication for TAVR, it is mandatory to clarify the characteristics of the patients who were judged as inoperable for conventional aortic valve replacement (cAVR). METHODS: Of 185 patients newly diagnosed as severe AS from March 2010 to April 2011, we studied the characteristics of 61 (33%) patients (mean age, 86 ± 8 years) who were judged as inoperable. RESULTS: Younger patients (<85 years old, n = 22) had more major comorbidities and lower left ventricular ejection fraction than older patients (≥85 years old, n = 39). Mean estimated mortality for cAVR by Japan score was 7.0% ± 7.4%. Japan score did not correlate to age and was calculated relatively low in the older age group (6.2% ± 7.0%) than the younger age group (8.3% ± 8.1%). CONCLUSION: One thirds of severe AS patients were judged as inoperable. In advanced age patients, age itself and other factors, which are not included in the conventional scoring systems, might have contributed to the decision making not to perform cAVR by cardiologists. Further study is necessary to define risk factors except for age.