Background: Transcatheter aortic valve implantation (TAVI) has been an alternative to conventional aortic valve replacement (AVR) in old and high risk patients. The goal of this study is to compare the early outcomes of conventional AVR vs. TAVI in high risk severe AS patients. Methods: From January 2008 to July 2012, 44 high risk severe aortic stenosis patients underwent conventional AVR, and 15 patients underwent TAVI. We compared echocardiographic data, periprocedural complication, and survival. The mean follow-up duration was $14.5{pm}10$ months (AVR), and $6.8{pm}3.5$ months (TAVI), respectively. Results: AVR group was younger ($78.2{pm}2.4$ years vs. $82.2{pm}3.0$ years, p<0.001) and had lower operative risk (Euroscore: $9.4{pm}2.7$ vs. $11.0{pm}2.0$, p=0.044) than TAVI group. There was no significant difference in early mortality (11.4% vs. 13.3%, p=0.839), and 1 year survival ($87.4%{pm}5.3%$ vs. $83.1%{pm}1.1%$, p=0.805). There was no significant difference in postoperative functional class. There was no significant difference in periprocedural complication except vascular complication (0% [AVR] vs. 13.3% [TAVI], p=0.014). TAVI group had more moderate and severe paravalvular leakage. Conclusion: In this study, both groups had similar periprocedural morbidity, and mortality. However, TAVI group had more greater than moderate paravalvular leakage, which can influence long-term outcome. Since more patients are treated with TAVI even in moderate risk, careful selection of the patients and appropriate guideline need to be established.