Background: one of the most important environmental pollutants is industrial wastewaters. Discharging of colorful industrial effluents to receptive waters can lead to eutrification and it has the carcinogenic and mutagenic properties. Therefore, the aim of this study is evaluation of Acid blue 15 dye removal by dried Azolla from aqueous solution. Material and methods: The Azolla biomass was dried in the sunlight, then it was crushed and sieved to particle sizes in range of 1-2 mm. Next treated with 0.1M HCl for a period of 5h. The azolla was washed with distilled water and it was used as adsorbent. The effect of operating parameters such as pH, contact time, AB 15 concentration and adsorbent dose on the AB15 removal efficiency was investigated. The dye concentration was measured by spectrophotometer (DR4000) in λmax =565nm. Results: In optimum condition (pH 3, contact time 90 min , adsorbent dose 10 gr/l and AB15 concentration 10 ppm), Application by azolla was able to remove 98% of AB15 from aqueous solutions. The equilibrium data is best fitted on Langmuir isotherm and the adsorption kinetic model follows pseudo-second model. Conclusion: The obtained results showed that the dried Azolla can be used as a high efficiency and low-cost adsorbent to treat of textile effluents.