Human infections due to group C streptococcus (SGC) are unusual. Among them, vascular compromise, especially aortic involvement, is extremely rare. A case of microbial aortitis with aneurysm formation, likely secondary to a SGC soft tissue infection, in a 61-year-old patient who was caring for a purulent leg wound of his horse, is presented. He was successfully treated with antibiotics and in situ aortic replacement with a prosthetic graft and an omental wrap. He remains well almost 2 years after surgical intervention. Aortic infection caused by SGC is a rare condition that can be successfully treated with in situ prosthetic graft replacement.