Some reports have suggested differential tissue deposition of dietary trace minerals such as Zinc (Zn) when supplied to farm animals either chelated to amino acids or as inorganic salts. To test this hypothesis, an experiment was conducted to determine the ultimate tissue distribution of Zinc in rats fed either a radioactively-labeled 65Zn-chelate or 65ZnSO4. The 65Zn-chelate was prepared by heating a solution of 65ZnSO4 and an equimolar mixture of glycine and methionine for 5 minutes at 90°C. The resulting chelate was then separated from unincorporated 65ZnSO4 by gel filtration chromatography. Ten 25-d old male wistar rats (mean weight 34.5 g) were randomized by weight into two groups (n = 5/group), fasted for 18 hours and given 0.4 ml (8 μg Zn, 1 μCi65Zn) of one or other labelled solution by gavage. Four hours later, animals were returned to their normal diet for the duration of the experiment. The 65Zn activity of the animals was determined two hours after administration and daily thereafter for 7 days.