A 79-year-old woman presented with a pulmonary infarction concurrent with a relapse of giant-cell arteritis during tapering off of prednisone. As no origin for thromboembolism could be found, it is very probable that the thrombosis of the branch of the pulmonary artery was superimposed on local giant-cell vasculitis. Rapid clinical and laboratory recovery was achieved with anticoagulant therapy and by increasing the prednisone dosage. The literature on this rare manifestation of giant-cell arteritis is reviewed.