Bentall operation is considered a gold standard of surgery in the treatment of ascending aortic aneurysm. This operation with en-bloc resection of ascending aorta and aortic valve requires aortic valve with two coronary bottoms re-replacements in a prepared composite graft. The four important locations for the pseudoaneurysm include proximal and distal composite graft anastomosis and two coronary bottom sites. However, many complications have been reported with this technique but the most serious complication associated with this operation is defined as pseudoaneurysm. We report an exceedingly rare case of subaortic ring pseudoaneurysm in retro composite graft position enclosed by infected surgical that was used to control bleeding in this location. Dehiscence occurred between the aortic ring and the underlying left ventricular muscle. The aortic ring was separated from the underlying muscle by the high tensile strength of sewing ring sutures. The pseudoaneurysm compressing the left atrium without communicating with any cardiac chamber and presenting with high fever (39°C), chills, a few months after Bentall operation. The patient underwent redo operation and repair of the dehiscence’s site. The 6-month follow-up revealed no recurrence of a pseudoaneurysm. The uniqueness of this case report is related to the site of pseudoaneurysm between the aortic ring and underlying left ventricular muscle that have not been reported in the medical literature so far.