We report two cases of simultaneous surgical treatment in patients with a concomitant abdominal aortic aneurysm (AAA) and hepatocellular carcinoma (HCC). The first patient underwent abdominal echography and was observed to have an abnormal hepatic mass. A consecutive computed tomographic (CT) scan showed an AAA, measuring 8 cm in size. The hepatic mass, which reached 5 cm in size, existed in the S5 and was strongly suspected to be HCC. The second patient was observed to have AAA by CT scan three years ago and also shown to have a hepatic mass, which reached 3 cm in size, in the S8. Both patients underwent a simultaneous resection. At first, a resection and reconstruction of the aneurysm was performed, followed by an extended right lobectomy and anterior segmentectomy of the liver. The postoperative course was uneventful and they were discharged on the 29th and 22nd postoperative day. To our knowledge, this is the first report of patients who underwent a successful simultaneous resection of an AAA and HCC.