Factors affecting silver biosorption by Saccharomyces cerevisiae biomass, obtained as a waste product from industry, were examined. Maximum removal of silver from solution was achieved within 5 min. Increasing the concentration of biomass in experimental flasks from 1 to 8 mg cm(-3) decreased both silver accumulation, from 224.7 to 89.5 mu mol Ag g(-1) dry wt, and associated H+ ion release, from 109.4 to 31.7 mu mol H+ g(-1) dry wt. The presence of 1.0 mol dm(-3) cadmium or methionine decreased silver biosorption by 40% and 93% respectively. Boiling in 100 mmol dm(-3) NaOH or 10 mmol dm(-3) sodium dodecyl sulphate decreased silver biosorption by 54% and 25% respectively. A temperature increase from 4 degrees C to 55 degrees C decreased silver biosorption by 9%. The metabolic state of the yeast had no effect on silver biosorption. Decreasing the pH of the silver solution caused a reduction in metal removal by the biomass.