Background: Dyes have complex molecular structures that are often toxic, carcinogenic, mutagenic, nonbiodegradable, and stable. Activated sludge is an adsorbents that basically in the biosorption process is an attractive technology for the separation and recycling of pollutants. Using sludge producing from wastewater treatment plants due to having low cost, availability, and reusability is growing. Methods: In this study, the dried activated sludge used for removal of Acid Cyanine 5R with concentrations of 25, 50, 75 and 100 mg/L. Effect of adsorbent concentration in weight of 0.2, 0.4, 0.8, 1.2, and 1.6 g/L, contact time, and pH were studied. Results: The results of the experiments showed that by increasing contact time up to 180 min increases dye removal efficiency and then remains constant. Also by increasing adsorbent dose, removal efficiency increased whilst by increasing pH, dye removal decreased. The results also show that the adsorption process follow pseodo second-order kinetic model with R2=0.9988. Conclusions: Due to the low cost and availability of dried activated sludge, it can be used as adsorbent in removal of dye from aqueas solutions.