Well-defined amphiphilic graft copolymer with hydrophobic polysulfone (PSU) backbone and hydrophilic poly(acrylic acid) (PAA) side chains were synthesized and characterized. For this purpose, commercially available PSU was converted to azido-functionalized polymer (PSU-N-3) by successive chloromethylation and azidation processes. Independently, poly(tert-butyl acrylate) (PtBA) with an alkyne-end-group is obtained by using suitable initiator in atom transfer radical polymerization (ATRP). Then, this polymer was successfully grafted onto PSU-N3 by click chemistry to yield polysulfone-graft-poly(tert-butyl acrylate), (PSU-g-PtBA). Finally, amphiphilic polysulfone-graft-poly(acrylic acid), (PSU-g-PAA), membranes were obtained by hydrolyzing precursor the PSU-g-PtBA membranes in trifluoroacetic acid. The final polymer and intermediates at various stages were characterized by H-1 NMR, FTIR, GPC, and SEM analyses. Protein adsorption and eukaryotic and prokaryotic cell adhesion on PSU-g-PAA were studied and compared to those of PSU-g-PtBA and unmodified PSU. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 110 117, 2011