A 66-year-old man experiencing fever and dyspnea was transferred to our hospital 2 years ago. He had been on hemodialysis for 30 years due to chronic renal failure and was observed as having aortic stenosis for 5 years. Severe mitral regurgitation and complete atrioventricular block caused by infective endocarditis (IE) were noted. Thus, he emergently underwent double-valve replacement (DVR) and pacemaker implantation. The range of infection extended widely to the right atrium and atrioventricular septum beyond the mitral annulus. The infection was suppressed by perioperative antibiotic therapy. Transthoracic echocardiography (TTE) revealed a cavity approximately 30 mm in diameter in the left ventricle, which was located under the mitral annulus, and it extended to the right atrium 3 months after the operation. A diagnosis of left ventricular pseudoaneurysm associated with IE was then made. Because of progressive expansion of the aneurysm, we performed another operation 2 years after the previous one. The pseudoaneurysm was located in the region of the Koch's triangle, which indicated that it was caused by mitral annular abscess. We closed the orifice of the aneurysm approximately 20 mm in diameter with a polyester patch with a diameter of 35 mm. Postoperative TTE showed that the pseudoaneurysm was thrombosed and had no blood flow. Pathological examination of the wall of the pseudoaneurysm revealed that it consisted of fibrous tissues without myocardium. We encountered a rare case treated by patch closure for the left ventricular pseudoaneurysm after DVR associated with IE.