The sorption of Pb(II) and Cu(II) ions from aqueous solutions by raw and pretreated Neurospora crassa fungal biomass was investigated in the batch mode. The influence of solution pH, equilibrium time and initial metal ion concentration using dried N. crassa cells as well as pretreatment on the sorption capacity of the biomass at optimum conditions were studied. The optimum conditions were pH 4.0 for Pb(II) and 5.0 for Cu(II) ions at initial metal ion concentration of 200 mg l-1 with equilibrium time of 15 min for both metal ions. Dried fungal cells exhibited the maximum sorption capacity (49.06 mg g-1) for Pb(II) ions while detergent treated cells showed the maximum sorption capacity (12.28 mg g-1) for Cu(II) ions. The experimental equilibrium data were evaluated by Freundlich and Langmuir isotherm models. Competitive biosorption of these metals was investigated in terms of sorption capacity and found that the biosorption capacity of biomass decreased with increasing the competing metal ion concentration. The involvement of functional groups on the surface of dried biomass in biosorption process is also discussed. © 2005 Elsevier Ltd. All rights reserved.