The goal of this project is to evaluate the chronic toxicity and carcinogenicity of zinc carbonate basic (ZCB) in rats exposed in the diet; zinc carbonate basic was used to supply zinc, an essential element and supplement. Some studies suggest that zinc deficiency is associated with carcinogenicity. 2-Year chronic toxicity and carcinogenicity studies are in the histopathology/report writing phase. The diets used in this study were either zinc deficient, contained an adequate amount of zinc or contained excess zinc. Keywords: toxicity, carcinogenicity, diet, zinc, zinc carbonate basic