Sternal infection after cardiac surgery is an infrequent post-operative complication. Aspergillus sternal osteomyelitis is a rarity. We review the case of a 77-year-old man with invasive aspergillosis of the sternum and left costal cartilage 23 years after undergoing cardiac surgery. The patient promptly underwent surgical irrigation and debridement, followed by antifungal therapy. Clinical suspicion of sternal fungal infection should be high in patients with mediastinitis with a history of cardiac surgery. Treatment should be prompt.