In order to evaluate the influence of leukocytes in whole blood on the standard blood bank conditions for storage, we compared several parameters of red cells, leukocytes and platelets in leukocyte-rich and leukocyte-poor whole blood over a storage period of 5 weeks. The leukocyte-depleted units were prepared by filtration with a leukocyte trapping filter (Sepacell R500A). Our data indicate improved storage conditions, made evident by significantly lower cell damage: smaller increases of elastase, beta-thromboglobulin and lactate dehydrogenase in leukocyte-depleted blood. This improvement was achieved in a simple two-bag system using only filtration, without addition of rejuvenating solutions. In addition, this procedure allows greater flexibility in the use of filtrated blood for transfusions.