The application of chemically activated (Phosphoric) Acacia nilotica leaves (PAN) for the removal of heavy metals Cu (II) and Ni (II) metal ions from aqueous solution was studied in a batch mode system. Adsorption of Ni (II) is more effective than adsorption of Cu (II) from aqueous solution by using PAN. PAN was characterized by using FTIR, SEM and XRD. Equilibrium, sorption, isotherms and kinetics are investigated. The effect of initial pH, contact time, initial metal concentration and adsorption dosage of Cu (II) and Ni (II) onto PAN have been investigated. The Langmuir and Freundlich adsorption models were applied to describe the isotherms and isotherm constants. Adsorption isothermal data could be well interpreted by the Langmuir model. The rate of adsorption was found to be confirmed by pseudo-second-order kinetics with a good correlation of R2 value [Ni (II) 0.988 and Cr (II) 0.971]. Desorption studies of metals using PAN also was conducted. These results suggest that Acacia nilotica leaves have a low-cost adsorbent potential for the heavy metal removal from waste water.