A B S T R A C TThe adsorption of Pb(II) and Cd(II) ions onto the biosorbent from leaves of Ramus Loranthi, Scurrula Parasitica L., family Loranthaceae, commonly known as mistletoe or Tam gui in Vietnam, (henceforth to be referred as mistletoe leaves) was studied. The results showed that adsorption equilibrium was established in 150 min of contact time. The maximum adsorption for both metals obtained was at pH 5.5. The time-dependent experimental data of Pb(II) and Cd(II) adsorption process well fitted the pseudo-second-order model. The Redlich-Peterson, Toth, and Langmuir models were appropriate to describe the adsorption process, indicating the chemisorption process onto mistletoe leaves. The maximum adsorbent capacity was increased with an increase in temperature. It was found to be 44.8, 47.85, 49.1, and 50.07 mg/g for Cd(II) and 59.76, 63.25, 66.3, and 68.53 mg/g for Pb(II) at 303, 308, 313, and 318 K, respectively. The positive value of ΔH indicated the endothermic adsorption process. The high adsorption capacity for Pb (II) and Cd(II) obtained in this study shown that mistletoe leaves are a potential biosorbent for removal of these metals from wastewater and contaminated water.