Peripheral haematopoietic progenitor cells are at present the most frequently used type of grafts for autologous transplantations. The reason is more rapid restoration of haematopoietic and less discomfort for the patient during collection. In children with a body weight of less than 25 kg apheresis is however difficult. These difficulties are in particular caused by transient removal of blond finto the separator and the poorer collaboration of young children. In children weighing 6 - 15 kg the separationset must be filled in advance with the transfusion preparation. In children weighing more than 15 kg an altered regime of separation and adequate haemoglobin levels before separation are sufficient. Results of the paediatric oncological clinic indicate that fit is rafe to obtain a graft of peripheral hematopoietic cells sufficient for transplantation (> 3 x 106 CD34+ cells/kg) and for four cycles of supportive treatment (>1 x 106 CD34+ cells/kg per cycle) in children weighing more than 6 kg.

        Key words: peripheral haematopoietic progenitor cells, cytapheresis in children weighing less than 25 kg