BACKGROUND: The UFO procedure is an established surgical technique to treat extensive endocarditis of the aortic or mitral valve with involvement of the intervalvular fibrous body (IVFB). This technique can be used for radical resection of the whole infected tissue. Independently of the size of the infected region it is unavoidable to replace both valves. In this high-risk re-do case we performed a modified so-called hemi-UFO procedure with preservation of the mitral valve. We present a 71-year-old male patient initially diagnosed with severe stenosis of the aortic valve. An aortic valve replacement with a 23-mm prosthesis was performed via partial upper mini-sternotomy. Eight weeks after surgery an echocardiogram revealed a large vegetation and severe regurgitation of the aortic valve prosthesis. The risk of death following reintervention heart surgery (EuroSCORE II) was calculated as 50.64%. We performed a re-do with full sternotomy. Intraoperatively it was observed that the aortic prosthesis was partially torn out. The aortic annulus exhibited circular infection with an abscess connecting to the left atrium. The tissue of the left atrial roof was partially destroyed, similar to a phlegmonous infection. We opened the left atrial roof and radically resected the infected tissue up to the IVFB. We prepared a custom-made conduit prosthesis of bovine pericardium with a 25-mm valve prosthesis. We replaced two thirds of the ascending aorta with re-implantation of the coronary arteries using the Bentall-de Bono technique. We were able to stabilise and implant the new aortic valve prosthesis with sutures through the opened left atrial roof. The stitches began close to the anterior mitral leaflet region and ended in the direction of the left ventricle outflow tract. All sutures were pericardium-pledgeted and were passed through a bovine pericardial patch. This patch formed a new mitral annulus and was used for the closure of the left atrial roof. We had to reconstruct the IVFB, the roof of the left atrium and the mitral annulus in the anterior (A1), middle (A2) and posterior (A3) segments. The patient was transferred to the intensive care unit with no inotropes and in sinus rhythm. The 3-year follow-up was uneventful. CONCLUSION: We showed a successful surgical treatment of aortic prosthesis endocarditis with involvement of the IVFB. We were able to perform a radical resection of the infected tissue, reconstruct and replaced all sacrificed tissue with biological tissue and preserved the native mitral valve in a modified hemi-UFO procedure.