The biosorption of As(III) ions onto the dry biomass of Aspergillus Aims isolated from the arsenic contaminated soil has been studied. The arsenic resistant fungal mycelia of Aspergillus flavus is used for the removal of As (III) ions from aqueous solution in the concentrations range of 50-500 mg/L. The effect of initial As (III) ions concentration (50-500 mg/L), pH (3, 4, 5) and temperature (25, 30, 35 degrees C) on arsenic removal has been investigated. The biosorption of As (III) ions by the biosorbent at different pH and temperature is increased as the initial concentration of As (III) ions is increased in the medium. The biosorption equalization is established in about 240 min and the amount of adsorbed As (III) ions do not change further with time. The maximum biosorption of As (III) ions by Aspergillus flavus is obtained at pH - 5. The maximum biosorption occurred at 35 degrees C. The As (III) ions adsorption data were analyzed using the first and the second order kinetic models. The experimental results fitted that the second-order kinetic model is the most appropriate equation to predict the biosorption capacity of Aspergillus flavus. Langmuir and Freundlich isotherms are used to evaluate the data and the regression constants are derived. Biosorption equilibrium data are best described by Freundlich isotherm model followed by Langmuir model.