Recently, a new type of modified cellulosic membrane (Hemophan) has been made available for the first clinical trials. In contrast to cellulose acetate membranes only about 5% of the hydroxyl groups of cellulose are substituted by tertiary amino groups. Objective of the present study was to assess the compatibility performance of this new membrane material. Therefore, 10 patients were dialyzed consecutively with membranes made of regenerated cellulose (Cuprophan) and modified cellulose. The modified cellulosic membrane showed less leukopenia. The generation of C3adesarg was reduced throughout the dialysis session. Both, the release of lactoferrin and elastase from granulocytes was diminished with the modified cellulosic membrane. All these differences reached the level of significance. Therefore, it seems that with Hemophan a more biocompatible type of cellulosic membrane has been introduced into hemodialysis treatment.