BACKGROUND: Mycotic aneurysm is an uncommon disease which could be fatal without appropriate treatment. Although standard therapy for mycotic aneurysms consists of resection of the infected aorta and in situ graft replacement, some treat with endovascular stent-grafting because patients may not tolerate graft replacement due to underlying diseases. There are 6 more reported cases of mycotic aneurysm caused by Edwardsiella tarda. With the exception of our case, all underwent resection and debridement of the infected aorta or vascular prosthesis. Herein we report the first case ever of mycotic aneurysm caused by E. tarda, successfully treated with stenting and suppressive antibiotic therapy without resection of the infected aorta. CASE PRESENTATION: A 65-year-old Japanese woman with cirrhosis and hepatocellular carcinoma complained of fatigue. Her work up revealed a ruptured aneurysm of the descending aorta. She went through endovascular stent-graft placement. Edwardsiella tarda grew from blood cultures, which led to the diagnosis of mycotic aneurysm. Edwardsiella tarda is a Gram negative bacillus which rarely causes infections in humans. In the case of bacteremia, its mortality is reported to be very high and all reported cases with mycotic aneurysm caused by E. tarda ended up with resection of the infected aorta. CONCLUSION: Our case shows that in the case of mycotic aneurysm caused by E. tarda, endovascular stent-graft placement could be an alternative to in situ graft replacement.