It has been shown in a previous study that monolithic columns can be used for downstream processing of different concentrates of clotting factor IX [K. Branović et al., J. Chromatogr. A 903 (2000) 21]. This paper demonstrates that such supports are useful tools also at an early stage of the purification process of factor IX from human plasma. Starting with the eluate after solid-phase extraction with DEAE-Sephadex, the use of monolithic columns has allowed much better purification than that achieved with conventional anion-exchange supports. The period of time required for separation is also much reduced. In up-scaling experiments, separations are carried out with 8, 80 and 500 ml columns. A volume of 1830 ml of DEAE-Sephadex eluate, containing a total of 27.6 g of protein and 48500 IU of factor IX is applied to the 500 ml monolithic column. This corresponds to a separation on a pilot scale. The results of this separation after up-scaling are comparable to those obtained with the 8 ml column on a laboratory scale.