This study focused on the removal of both cationic and anionic dye from an aqueous solution using a natural product. Evaluation was made of the biosorption of methylene blue (MB) and Indigo carmine (IC) as a basic dye and an acid dye, respectively, from an aqueous solution using the dried fruits of Elaeagnus angustifolia. The experimental parameters such as pH of the solution, initial dye concentration, and contact time, were optimized to achieve quantitative removal. The quantitative biosorption of dyes was achieved as 200 mg L –1 of MB within 10 min at pH 7, 25 mg L –1 of IC within 10 min at pH 2. The maximum biosorption capacity was 344.8 mg g –1 for MB and 9.7 mg g –1 for IC at room temperature. The pseudo-first-order model and pseudo-second-order models were used to explain the biosorption kinetics. The second order model best explained MB and IC biosorption onto E. angustifolia. The experimental results showed that the use of E. angustifolia as a biosorbent is fast and effective, thereby indicating that it could be an attractive alternative for the removal of anionic and cationic dyes from dye wastewater.