OBJECTIVES: For estimating the cost-effectiveness of interventions to avert blood-transfusions it is important to estimate the costs of one unit of allogeneic blood. An example of such an intervention is administration of erythropoietin. Objective of this study was estimating the costs per unit of erythrocytes in the Netherlands from a societal perspective. METHODS: For the estimation of the costs we followed the path from donor to patient. In this path 6 steps were elaborated: donation, production, transport, storage and preparation, administration and the consequences of administration. In these different steps the cost-consequences were estimated. RESULTS: Although not all cost-factors could yet be identified, the cost-estimate is €240,- for a unit of erythrocytes. The indirect costs are responsible for approximately 3% of the unit costs. The production and transport part by the Dutch blood banks is responsible for the majority of the costs. CONCLUSIONS: Internationally cost-estimates vary widely. Cost-estimates for the United States, United Kingdom, Sweden and Canada vary from approximately €130,- to €930,-. For the Netherlands we estimated the unit costs for a unit of erythrocytes at €240,- from a societal perspective.