Serratia marcescens is a facultative anaerobic bacillus that very rarely causes sternal infections. We describe a sternal abscess resulting from chronic S. marcescens infection that presented 13 years after coronary artery bypass graft surgery (CABG). A 71-year-old diabetic man presented 13 years after CABG with a new distal sternal "mass" that intermittently drained purulent fluid. He was treated with oral antibiotics, but the symptoms persisted. Exploration revealed an abscess extending to the sternal body. A non-absorbable braided suture and a sternal wire were removed, but a sinus tract remained despite further antibiotics and conservative care. Subsequent computed tomography and bone scintigraphy revealed a substernal soft tissue density with bone involvement. An abscess cavity was excised from the substernal anterior mediastinum. Another non-absorbable braided suture was removed. Cultures grew carbapenem-resistant S. marcescens. Nosocomial or hospital-associated clusters of S. marcescens infection are known, but isolated infections seldom occur. S. marcescens infections in cardiac surgery patients are unusual. Only a single report described a chronic sternal infection resulting from S. marcescens that was identified 15 years after an initial episode caused by the same organism in a heart transplant recipient who was immunocompromised. Diabetes and non-absorbable braided sutures placed for hemostasis at the wire sites were probably contributing factors to our patient's chronic infection. This report described the presentation and treatment of a chronic S. marcescens sternal abscess that occurred 13 years after CABG. Chronic sternal infections due to this organism in cardiac surgery patients are exceeding rare. Published by Elsevier Ltd.