Biosorption of cadmium by a cadmium tolerant variant of Aspergillus niger in presence of lead, nickel and chromium from synthetic aqueous culture medium has been studied. Aspergillus niger AB10 absorbed 98.2% cadmium from culture medium containing 2 μg/ml cadmium under optimized physical and chemical parameters. More than 90% of cadmium was absorbed by Aspergillus niger AB10 from culture medium containing other toxic heavy metals. Cadmium biosorption capacity decreased sharply when lead, nickel and chromium were added at a time at a concentration over 5.0 μg/ml, 2.5 μg/ml and 5.0 μg/ml respectively and over 5.0 μg/ml when added in combination.