This paper reports studies on the removal of toxic trace metals (nickel separately, and simultaneously with cobalt) from aqueous solutions by employing fungal biosorbents, PFB1 and PFB2, which were developed in our laboratory. The observed maximum equilibrium uptake of nickel on the biosorbent was 214 mg.g(-1) (PFB1) and 110 mg.g(-1) (PFB2). The average efficiency for nickel removal was 84.5% (PFB1) and 60.8% (PFB2). The equilibrium uptake of nickel followed first-order Langmuir kinetics in the case of PFB1 and second-order Langmuir kinetics in the case of PFB2. Studies on simultaneous removal of cobalt and nickel indicated that the extent of secondary interactions between cobalt and nickel can be quantified by the change in Langmuir equilibrium constants for both metals. A mathematical model based on Fick＇s law of diffusion and Langmuir adsorption was developed to simulate the kinetics of nickel removal. The model was able to predict the experimentally observed kinetics well. From the simulations, the diffusivity of nickel in PFB1 was found to be 1.6 x 10(-8) m(2).s(-1). Desorption studies indicated that it was possible to reuse the biosorbent over three sorption-desorption cycles, and that acidic solutions desorbed better than basic or salt solutions. Among the desorbents studied, HCl and CaCl2, with dt sorption efficiencies equal to 73.2 and 74.1%, respectively, for PFB1 and 70.0 and 63.1%, respectively, for PFB2 at the end of three cycles, were found to be the best desorbents.