This paper reports the design, preparation and characterization of cellulose affinity membranes for antibody purification using a new methodology. Cellulose membranes were prepared from polymerionic liquid solutions, namely 1-butyl-3-methylimidazolium chloride ([BMIM][CI]), by the water induced phase inversion process. After functionalization with a synthetic ligand 2-(3-aminophenol)-6-(4-amino-1-naphthol)-4-chloro-s-triazine (ligand 22/8), these were evaluated as affinity supports for human immunoglobulin G (IgG). Membranes were characterized in terms of morphology (SEM), porosity (mercury porosimetry), hydrophilicity (contact angle measurement), transport properties (permeability) and mechanical performance (DMA). Membranes prepared with varying cellulose contents (5 and 10 wt.% cellulose in ionic liquid solutions) lead to films with different properties. The 10 wt.% cellulose membrane presented enhanced morphological and mechanical properties, however, the morphology of this membrane was significantly altered after ligand coupling. Adsorption isotherms for human IgG onto 10 wt.% matrix activated with ligand 22/8 were obtained. Preliminary results showed that the bovine serum albumin (BSA), a model impurity, did not adsorb onto the membrane while up to 6 mg IgG/g was bound and 2 mg IgG/g recovered. (C) 2009 Elsevier B.V. All rights reserved.