Disclosed is a hydrophilic material characterized in that the material comprises a copolymer composed of a monomer (A) having a polyalkylene oxide unit and a polymerizable carbon-carbon double bond in its molecule, a methacrylic ester monomer or an acrylic ester monomer (B) and a monomer (C) having a polymerizable carbon-carbon double bond other than the monomers (A) and (B), and the content of the monomer (C) is not less than 5% by weight and not more than 90% by weight, and a semipermeable membrane made therefrom. The present invention provides a hydrophilic material which can be dissolved in a solvent, can be easily formed and is excellent in antithrombotic and antifouling properties, and further provides an antithrombotic material and a semipermeable membrane. These materials can be appropriately used in the medical field and as water-absorbent and antifouling materials.