In the present study, the adsorption of zinc (Zn 2+) and lead (Pb 2+) from aqueous solutions by nanostructured cedar leaf ash as biosorbent was investigated in batch tests under different experimental conditions. The chemical and morphological structures of biosorbent were investigated by scanning electron microscopy (SEM), elemental analyzer (CHNSO), particle size analyzer (PSA), X-ray Fluorescence spectroscopy (XRF) and Fourier-transform infrared spectroscopy (FTIR). The effect of different parameters such as solution pH, contact time and adsorbent dosage were investigated on the biosorption of two studied metals by nanostructured cedar leaf ash. The biosorption process was found to be relatively fast and equilibrium was achieved within 30 min for Zn 2+ and Pb 2+. The adsorption data were analyzed using different isotherm models (Langmuir, Freundlich, Redlich–Peterson and Sips (Langmuir–Freundlich)) and kinetic models (pseudo-first-order, pseudo-second-order and intraparticle diffusion). Results revealed that pseudo-second-order kinetic model could well describe the adsorption kinetics of Zn 2+ and Pb 2+ biosorption, and Sips (Langmuir–Freundlich) model was found to fit well for Zn 2+ and Pb 2+ adsorption. The maximum adsorption capacity from Langmuir model was calculated as 7.23 and 4.79 mg g −1 for Pb 2+ and Zn 2+ , respectively.