A composition useful for separating lipoproteins, such as high density lipoprotein (HDL), low density lipoprotein (LDL), very low density lipoprotein (VLDL) and modified lipoproteins with a high degree of accuracy by ion-exchange based procedures. The composition comprises an organic particle having a hydrophilic surface onto which ion-exchange groups are introduced and which is formulated so as to provide a high enough degree of hydrophilicity to prevent irreversible absorption of lipoproteins, but which is not so high as to block the pores of the ion exchange particles and prevent adequate retention and separation of lipoproteins. A method for making a composition for separating lipoproteins comprising seed polymerization of organic particles, hydrophilic treatment of the organic particles by introducing 0.1-45% of a compound (B) having a cyclic ether group and/or a hydrophilic group and a polymerizable unsaturated double bond into organic polymer particles (A) by an addition reaction, and copolymerizing with the addition product of (A) and (B) 5-60% of a polymerizable vinyl monomer (C) having a cyclic ether group or/and a hydrophilic group to form particles (D) having a hydrophilic surface, and introducing an ion exchange group in an amount ranging from 0.15 milliequivalent or less per 1 g of dry particles (D).