To develop a bioartificial renal tubule system using renal tubular cells and porous polymer membrane hollow fibers, long-term maintenance of a confluent monolayer and the functionally differentiated condition of cells is essential. We examined the proliferation and functional differentiation of LLC-PK1 (Lewis-lung cancer porcine kidney 1) cells on two types of membranes: polysulfone and cellulose acetate. Cell proliferation was significantly higher on the polysulfone membrane than on the cellulose acetate membrane, and was enhanced by coating the membranes with various extracellular matrices. Confluent monolayer formation of cells was observed on matrix-coated polysulfone membrane but not on matrix-coated cellulose acetate membrane within 1 week. Cell proliferation continued for 3 weeks after confluent monolayer formation. Messenger RNA (mRNA) expression of glucose transporters, indicators of the functional differentiation of the LLC-PK1 cells, was observed in the polysulfone and cellulose acetate membrane groups, but was not observed in the nonporous polystyrene plate group under subconfluent conditions. Expression of glucose transporters mRNA was maintained for 3 weeks after confluent monolayer formation. Polysulfone membrane is more suitable than cellulose acetate membrane for a bioartificial renal tubule system with regard to LLC-PK1 cell proliferation. Extracellular matrix coating of the membrane further improves cell proliferation.