The biosorption of Cd(II) and Cu(II) ions on Botrytis cinerea (B. cinerea) fungal biomass has been investigated as a function of initial pH, contact time and initial metal ion concentration in a batch system. Optimum conditions were determined by heat inactivated biomass before pretreated biosorbent performances were investigated. Maximum biosorption capacities of Cd(II) and Cu(II) ions on B. cinerea were found to be 17.03 ± 0.76 mg/g and 9.23 ± 0.64 mg/g, respectively. The adsorption data obtained under optimum conditions were evaluated by Freundlich and Langmuir isotherm models. Competitive biosorption of these metals was also investigated in terms of biosorption capacities and found that the biosorption capacity of biomass decreased with increasing the competing metal ion concentration. The biosorbent was regenerated using 10 mM HCl solution, with up to 96% recovery and reused five times in biosorption-desorption cycles successively. Physical and chemical pretreatment methods were found to increase the biosorption capacity of biomass in comparison with the live biomass. The biosorption mechanism of heat inactivated biosorbent was also evaluated by chemical and instrumental analysis including infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and X-ray energy dispersion analysis (EDAX). © 2005 Elsevier Ltd. All rights reserved.