The equilibrium sorption isotherms of 3 reactive dyes (C. I. Reactive Yellow 84, C. I. Reactive Red 141, C. I. Reactive Blue 160) and their binary mixtures adsorbed on prewetted wool fiber were investigated. The kinetic studies were carried out at pH <= 7 and 80 degrees C in dye solutions containing 20 g/L NaCl. It was reported that binary mixtures of these reactive dyes have lower sorption values than the dyes alone, at the same dye concentration, pH and temperature. The isotherms obtained are Langmuir type. The rate parameters of adsorption kinetics decrease with increasing dye concentration.