last few decades. In this study, the lyophilized cells of Pleurotus eryngii (mushroom) were used as an inexpensive biosorbent for Cd(II) and Pb(II) removal from aqueous solutions. The effect of various physicochemical factors on Cd(II) and Pb(II) biosorption such as pH (2.0-7.0), initial metal concentration ($0.0-300mg;L^{-1}$), temperature, fungal biomass and contact time (0-120 min) were studied. Optimum pH for removal of Cd(II) and Pb(II) was 6.0, and the contact time was 45 min at room temperature. The nature of biosorbent and metal ion interaction was evaluated by Infrared (IR) spectroscopic technique. IR analysis of mushroom biomass revealed the presence of amino, carboxyl, hydroxyl and methyl groups, which are responsible for biosorption of Cd(II) and Pb(II). The maximum adsorption capacities of P. eryngii for Pb(II) and Cd(II) calculated using Langmuir adsorption isotherm were 82.0 and $16.13mg;g^{-1}$, respectively. The adsorption isotherms for two biosorbed heavy metals were fitted well with Freundlich isotherm as well as Langmuir model with correlation coefficient ($r^2$>0.99). Thus, this study indicated that the P. eryngii is an efficient biosorbent for the removal of Cd(II) and Pb(II) from aqueous solutions.