The aim of this study was to investigate the bile salts adsorption behavior of the diethylaminoethyl (DEAE)-chitosan, in vitro. In order to prepare the DEAE-chitosan, where the DEAE groups are specifically introduced onto 6-OH groups of chitosan with minimal by-product, DEAE-chitin was prepared by reacting chitin with N,N-diethylaminoethyl chloride, and direct N-deacetylation of DEAE-chitin was carried out in 10% of an aqueous sodium hydroxide solution containing sodium borohydride. DEAE chitosan samples were incubated with cholic acid sodium salt and deoxycholic acid sodium salt in a tromethane buffer solution (pH 7.5) for 1 hour, and the bile salts adsorption performances of the samples were examined by HPLC. The modified chitosan samples showed improved bile salts adsorption performances compared to chitosan, and the absorption amount of bile salt to the samples increased with increase in the DEAE groups introduced. In most cases, the adsorption amount of deoxycholate to the samples was greater than that of cholate.