A new highly hydrophilic crosslinking agent, 2,3-dihydroxybutane-1,4-diyl dimethacrylate (DHDM), was synthesized from 1,2:3,4-diepoxybutane by the reaction with methacrylic acid. Highly hydrophilic spherical particles were prepared by suspension copolymerization of 2-hydroxyethyl methacrylate (HEMA) with DHDM in an aqueous medium in the presence of cyclohexanol and 1-dodecanol as inert diluents. Porous properties of HEMA-DHDM copolymer were compared with those of commercially available poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) and poly(glycidyl methacrylate-co-ethylene dimethacrylate) sorbents.