Acquired haemophilia is a rare, but often life-threatening bleeding disorder caused by autoantibodies, mostly directed against factor VIII (FVIII inhibitor). The incidence of acquired haemophilia, which most commonly affects patients over 50 years of age, is estimated between 0.2 and 1 million per year. Although its aetiology remains obscure, 40-50% of cases are associated with other conditions, such as pregnancy, malignancies, drugs and autoimmune disorders as rheumatoid arthritis, systemic lupus erythematosus and Sjögren's disease. We report the case of a 69-year-old patient with spontaneously acquired FVIII inhibitor secondary to polymyalgia rheumatica (PMR)/arteritis temporalis (AT). Our case illustrates that PMR/AT can be added to the list of autoimmune disorders associated with acquired haemophilia due to FVIII inhibitor.