Chemical and biological treatment of dye- containing wastewaters is difficult due to the low adsorption level and chemical stability of dyes. Activated carbon is usually used for adsorption of these materials, but because of high prices and restore problems, researchers trying to find available low-cost materials with high adsorption. In this study, bagasse was used for adsorption of Remzol Black B dye and its capability was examined. Variables were concentration, temperature, pH and contact time, and the degree of adsorption was examined in different situations. Then, adsorption isotherm according to Langmuir and Freundlich models was investigated. The results showed that the adsorption efficiency depends more on pH of solution and less on temperature of the solution. Maximum adsorption of Remzol Black B dye by bagasse occurred in the first 15 minutes of contact. The study of adsorption isotherm showed that both models are suitable for description of adsorption of Remzol Black B dye by bagasse. Maximum adsorption of Remzol Black B dye by bagasse was calculated as 7.51 mg/g. Results of this study showed that bagasse could be used as a low-cost bio adsorbent for the adsorption of Remzol Black B from aqueous solution.