This study was designed to determine the effect of zinc on the biological half-lives of 65Zn in whole body and liver and on distribution of 65Zn in different organs of rats following nickel toxicity. Sprague-Dawley (SD) rats received either nickel in the form NiSO4.6H2O at a dose of 800 mg/L in drinking water, zinc in the form of ZnSO4.7H2O at a dose of 227 mg/L in drinking water, and nickel plus zinc or drinking water alone for a total duration of 8 wk. All of the rats were injected with a tracer dose of 0.37 MBq 65Zn at the end of the treatment period. The effects of different treatments were studied on biological half-lives of 65Zn in whole body and liver and on the distribution of 65Zn in different organs of rats. In the present study, we have noted that nickel treatment to normal rats caused a significant decrease in the slow component (Tb2) in liver, which improved following zinc supplementation. Nickel administration to normal-diet-fed animals caused significant lowering in the percentage uptake of 65Zn values in the brain, liver, and intestine. However, the administration of zinc to nickel-treated rats improved the status of 65Zn in different organs. The Tb2 in the liver and the percentage uptake of 65Zn values elevated following zinc supplementation to nickel-treated rats.