Transcatheter aortic valve replacement (TAVR) has revolutionized the prognosis of intermediate- or high-risk patients with severe aortic stenosis, particularly among older adults. However, in possible candidates for surgical aortic valve replacement (SAVR), the implantation of expensive prostheses may be questionable in an era when healthcare costs are becoming a major concern. In this retrospective analysis of a single Japanese center, we focused on patients aged over 80 years; the objectives of this study were: (1) to compare TAVR and SAVR in terms of total hospitalization costs and (2) to describe the itemized cost of TAVR and SAVR to identify patients aged over 80 years in whom TAVR or SAVR would be cost-effective. A total of 146 patients aged over 80 years who underwent TAVR or SAVR for severe aortic stenosis were included. These patients were divided into a high-risk group (Society of Thoracic Surgeons [STS] mortality score > 8%; 36: TAVR and 12: SAVR) with 48 patients and a non-high-risk group (STS mortality score < 8%; 45: TAVR and 53 SAVR) with 98 patients. No 30-day mortality was observed in either group. In both groups, postoperative intensive care unit stay and hospital stay were longer with SAVR than with TAVR. In the non-high-risk group, the total cost was comparable for TAVR and SAVR; however, in the high-risk group, the total cost was significantly higher with SAVR than that with TAVR. A breakdown analysis of the total cost in the high-risk group showed both pre- and postoperative costs to be significantly higher with SAVR than with TAVR; however, operative costs were higher with TAVR. Up to 3 years, the overall survival in both groups did not significantly differ between TAVR and SAVR. Our findings suggest that from the perspective of total medical costs, TAVR is more suitable than SAVR for high-risk older adults.