The spread of H5N1, an avian influenza A virus, to many countries and the direct infection of humans by this virus have increased awareness of the likelihood of a pandemic among humans. The potential impact of pandemic influenza on the safety of the blood supply should be small because of the limited viremia and the nature of respiratory tract infection of influenza viruses. However, the potential impact of pandemic influenza on the availability of the blood supply could be significant because of reduced donation from blood donors and reduced staff capacity at blood centers during a pandemic. On the other hand, there could be reduced hospital admissions and reduced transfusions, at least for certain blood products, which should result in reduced demand for blood products. Studies are needed to further assess the likely impact of a pandemic on the blood supply and also of the possible intervention options.