A ciliate protozoan, Euplotes mutabilis, isolated from heavy metal laden industrial wastewater, has been shown to tolerate multiple heavy metals thus suggesting its significance in bioremediation of industrial effluents. This ciliate tolerated Zn(2+) up to 33 microg/mL, Cd(2+) up to 22 microg/mL and Ni(2+) up to 18 microg/mL. The ciliate could uptake 85% Zn(2+), 84% of Cd(2+) and 87% of Ni(2+) after 96 h of inoculation of growth medium containing 10 microg/mL of Zn(2+) and 5 microg/mL of Cd(2+) and Ni(2+), with actively growing ciliates. After 6 days of incubation the ciliate removed 87% Cd(2+), 92% Ni(2+), and 93% Zn(2+) from the wastewater. The heavy metal uptake capability of Euplotes mutabilis may be employed for metal detoxification operations.