Background: Colour in textile industry and dying wastewater is considered as one of the most important environmental pollutants. The aim of this study is determining the efficiency of removal of reactive Red 198 and Blue 19 by activated carbon that is extracted from the leaves of Mesquite. Methods: This research is an experimental –laboratory study in which the effect of variables in the efficiency of color removal from synthetic wastewater was studied. The parameters examined were the pH, reaction time, adsorbent dose and initial concentration of dye. Also, adsorption behaviour of dyes was evaluated by Freundlich and Langmuir isotherms. Results: The results show that the color removal efficiency decreased with increase in pH, but increased with the increase in adsorbent dose, contact time and initial dye concentration. After 40 minutes, the reaction reached equilibrium and then clearly dropped. Color removal efficiency of reactive Red 198 in dye concentration of 60mg/l reached about 85.81% and for reactive Blue 19 in dye concentration 240 mg/l reached 97.43%. Langmuir adsorption model and Freundlich model were respectively the best models that the adsorption process followed for Reactive Red 198 and Reactive Blue 19. Conclusion: The efficiency of the prepared adsorbent in the removal of dyes from aqueous environment showed that it can be considered as an effective and inexpensive adsorbent in colored wastewater treatment processes.