Improved biosorption of uranium by Kluyveromyces marxianus IMB3 biomass was achieved by increasing the electric field strength of delivered pulses from 1.25kV/cm to 2.5kV/cm. Although this had little or no effect on the maximum biosorption capacity (q(max)), at low concentrations of uranium the amount bound to the biomass increased from 70 to 140mg uranium/g biomass. Significant increases in the maximum biosorption capacities (119 - 180 mg uranium/g biomass) were observed when the pulse field strength was increased from 2.5kV/cm to 3.25kV/cm.