Staphylococcus pseudintermedius is a common commensal and opportunistic canine pathogen with emerging pathogenicity in humans. We describe the first case of invasive S. pseudintermedius infection causing aortitis and mycotic aneurysm in an 83-year-old patient, treated successfully with flucloxacillin. This case highlights the potential for S. pseudintermedius to cause serious endovascular infection in humans.