Six types of cationic starch derivatives were prepared. These types were (1) cationic starch derivatives containing primary, secondary, and tertiary amino groups and quaternary ammonium salt and (2) etherified and grafted cationic starch derivatives. These cationic starch derivatives were treated with three types of dyes, an acid dye, a hydrolyzed reactive dye, and a direct dye. Different factors affecting the dye sorption value (mmol/100 g of sample) were been studied. These factors were the pH of the medium, treatment time, amine type, amine content, dye type and molecular size, and the distance between the amine groups. The dye sorption value and the sorption efficiency percentage were determined. The dye sorption value increased with increasing amine content to a maximum value and then decreased. This phenomenon occurred with all of the amine types. The maximum dye sorption values on with the acid dye depended on the amine type. These values were 73.8 (at an amine content of 155), 90 (at an amine content of 150), 84.9 (at an amine content of 133), and 72.5 (at an amine content of 75) for primary, secondary, and tertiary amines and the quaternary ammonium salt, respectively. The sorption efficiency percentage at these maximum values were 47.6, 60, 63.8, and 96.3%, respectively. The maximum sorption values were acid dye > hydrolyzed reactive dye > direct dye. The dye sorption value and the sorption efficiency percentage of the etherified cationic starch derivatives had higher values than that of the grafted cationic starch derivatives. The prepared cationic starch derivatives that had amine contents of 155, 150, 133, and 75 m atom/100 g of sample for primary, secondary, and tertiary amines and the quaternary ammonium salt, respectively, had the best ability to adsorb anionic dyes. (C) 2004 Wiley Periodicals, Inc.