Publisher Summary This chapter discusses column packings for high-performance liquid chromatography (HPLC) and medium-pressure liquid chromatography (MPLC) of biopolymers and biooligomers. Chromatographic packing materials can be classified according to diameter and geometric structure of the particles into three classes—namely, (1) macroporous, (2) pellicular, and (3) microparticular. Packing materials for chromatography are sometimes used in the naked (nonbonded) form. In addition, because of the irreversible sorption of many biopolymers and biooligomers, for the purpose of size-exclusion chromatography (SEC) or normal-phase chromatography (NPC), the surface of silica or porous glass is modified with an organic hydrophilic or polar layer. Uncoated materials (as supports, both for the preparation of special chromatographic packings by coating with various layers and for direct chromatography) can be classified according to chemical composition. Most supports are silica (or sometimes porous glass), alumina being used only exceptionally, but resins are also used in reversed-phase chromatography (RPC). Polysaccharide xerogels, which are cross-linked dextran and agarose, are well known efficient packings for the low-pressure gel permeation chromatography of biopolymers.