The interest of centralization of preparations of chemotherapy drugs is in addition to its economic aspect, to secure drugs circuit. The aims of this study are to determine needs in employees and equipments of 11 theoretical levels of production from 1,000 to 50,000 preparations per year and to determine the cost of chemotherapy's preparation for each theoretical unit. The operating cost was divided in four areas of expenditure: employees (66-78%), investment (5-15%), maintenance (3-15%) and consumables (4-16%). If we consider the 11 units, the theoretical cost varies between 27.4 € for a unit with 50,000 preparations per year and 114.1 € for a unit with 1,000 preparations per year. This study shows the importance of setting up an optimal unit of preparations according to its activity and highlights the high cost's variation in relation to the activity of the unit.