Application of chitosan bead as a low-cost adsorbent for removing Reactive Brown 10 (RB 10) from aqueous solution was investigated. The presence of -NH2 and -OH functional groups on chitosan beads were evident from the Fourier transform infrared (FTIR) spectrum. The changes on the surface morphology of the chitosan beads before and after sorption were analysed. Dye sorption was found higher with a longer contact time, lower dye concentration and greater adsorbent dosage. The optimum pH and adsorbent dosage for the adsorption of RB10 were pH 4–6 and 0.04 g, respectively. Both Langmuir and Brunauer, Emmett and Teller (BET) isotherm were determined as the appropriate model to describe the behaviour of the adsorption process. The maximum adsorption capacity was about 22 mg g–1. The significant variables in affecting the RB 10 uptake was identified using the Plackett-Burman (PB) program.