Publisher Summary Gel chromatography is also commonly known as “gel filtration,” “gel-permeation,” or “molecular-sieve chromatography.” This technique is based on the decreasing permeability of the three-dimensional network of a swollen gel to molecules of increasing size. In specific, if a solution containing a mixture of solutes of different molecular sizes is passed through a column packed with a suitable gel, the smaller molecules penetrate farther into the gel pores than do the larger, and are therefore retained for a longer time on the column. The solutes are thus eluted in the order of decreasing molecular size. This chapter emphasizes on the fundamental aspects of gel chromatography technique that are most likely to arise in carbohydrate chemistry. It illustrates the applicability of gel chromatography to a wide variety of carbohydrates. This procedure is considered as a rapid and relatively simple method for separating substances that differ in molecular size, or for fractionating polymers, such as polysaccharides, having broad molecular weight distributions.