Dyes are one of the most hazardous chemical compound classes found in industrial effluents and need to be treated since their presence in water bodies reduces light penetration, precluding the photosynthesis of aqueous flora. In the present study a new activated carbon was prepared from Cotton stalk using phosphoric acid in a Tubular furnace and designated as Cotton Stalk Tubular furnace Carbon (CSTC) was used as an adsorbent for the successful removal of Reactive Red dye from aqueous solutions. The effect of various operating parameters such as initial concentration of dye, contact time, adsorbent dosage and initial pH was investigated in order to find the optimum adsorption conditions. Different isotherms were used to identify the possible mechanism of the adsorption process. The optimum pH for removing of RR dye from aqueous solutions was found to be 2 and predicted maximum adsorption capacity for RR dye was obtained as 71.43 mg/g for the chosen experimental conditions.