Introduction: Mediastinitis is a rare, severe condition associated with increased morbidity and mortality rate if recognized late or treated improperly.We present a case of mediastinitis in a previously healthy young man with past surgical history of aortic valve repair 16 months earlier following a routine dental procedure.Case presentation: A 47-year-old man was admitted to our hospital upon recommendation of his cardiologist.The patient complained of right sided chest pain and tightness radiating to the right side of his neck and right arm preceded by flu-like symptoms and fever for 2 days.Asymmetry of his chest wall with right-sided prominence was noted.Following admission, he underwent a chest computed tomography (CT) scan which revealed radiographic evidence of infectious mediastinitis with adjacent soft tissue swelling of the fight pectoralis major and minor muscles.Subsequently,he underwent a CT guided abscess aspiration draining serosanguinous fluid.Antibiotics were administered, his condition quickly improved and he was discharged nine days from admission.Conclusion: Mediastinitis is a life-threatening infection which may occur during postoperative period following cardiovascular surgery.It may also result from an infection extending from the oropharynx inferiorly through the deep spaces of the neck as a descending necrotizing mediastinitis.We report a unique case of mediastinitis occurring in a patient 16-months after he underwent aortic valve repair secondary to acute aortic dissection.He also had routine dental work 1-month prior to the development of mediastinitis.Clinicians should be alert to the various causes and subclinical manifestations of mediastinitis to prevent severe complications.