We report a patient who presented with high fever; a unilateral, palpable tender swelling along the right shin; and effusions in knee and ankle joints leading to the diagnosis of hypertrophic osteoarthropathy (HOA). The diagnostic workup revealed an infected vascular graft that had been implanted 2 years before because of a ruptured infrarenal aortic aneurysm as the cause of HOA. The patient was treated successfully with antibiotics and surgically replacing the infected graft. Hypertrophic osteoarthritis is a clinical entity characterized by digital clubbing, periostitis, and synovial effusions. Primary and secondary forms have been described. Secondary HOA develops as a consequence of various diseases, mainly intrathoracic malignancies. Vascular graft infection, as reported here, is a rare cause of HOA. This case underlines the typical clinical features of HOA and the importance of a prompt and comprehensive diagnostic workup in cases of HOA. Our aim is to sharpen the awareness of its multiple underlying causes. Unilateral HOA is a rare but strong and important sign of infection of vascular prosthesis.