The incidence of living haemophiliacs in Sweden (total population 8.1 millions) is about 1:15,000 males and about 1:30,000 of the entire population. The number of haemophiliacs born in Sweden in 5-year periods between 1931-1975 (June) has remained almost unchanged. The total number of haemophilia families in Sweden is 284 (77% haemophilia A, 23% haemophilia B) with altogether 557 (436 with A and 121 with B) living haemophiliacs. Of the haemophilia A patients 40 % have severe, 18 % moderate, and 42 % mild, haemophilia. The distribution of the haemophilia B patients is about the same. Inhibitors have been demonstrated in 8% of the patients with severe haemophilia A and in 10% of those with severe haemophilia B. There are 2 main Haemophilia Centres (Stockholm, Malmo) to which haemophiliacs from the whole of Sweden are admitted for diagnosis, follow-up and treatment for severe bleedings, joint defects and surgery. Minor bleedings are treated at local hospitals in cooperation with the Haemophilia Centres. The concentrates available for treatment in haemophilia A are human fraction 1-0 (AHF-Kabi), cryoprecipitate, Antihaemophilic Factor (Hyland 4) and Kryobulin (Immuno, Wien). AHF-Kabi is the most commonly used preparation. The concentrates available for treatment in haemophilia B are Preconativ (Kabi) and Prothromplex (Immuno). Sufficient amounts of concentrates are available. In Sweden 3.2 million units of factor VIII and 1.0 million units of factor IX are given per year. Treatment is free of charge. Only 5 patients receive domiciliary treatment, but since 1958 we in Sweden have practised prophylactic treatment of boys (4–18 years old) with severe haemophilia A. At about 5-10 days interval they receive AHF in amounts sufficient to raise the AHF level to 40–50%. This regimen has reduced severe haemophilia to moderate. The joint score is identical with that found in moderate haemophilia in the same age groups. For treatment of patients with haemophilia A and haemophilia B complicated by inhibitors we have used a large dose of antigen (factor VIII or factor IX) combined with cyclophosphamide. In most cases this treatment produced satisfactory haemostasis for 5 to 30 days and prevented the secondary antibody rise. * Presented at the Symposium held during the 3rd meeting of the European and African Division of the International Society of Haematology in London, August 1975.