Zinc (Zn) is an essential trace element that is needed for growth, bone development, and immune competence. Inorganic Zn sources such as Zn oxide and Zn sulfate (ZnSO₄) are most commonly used in swine diets. However, because of low bioavailability of Zn the inorganic Zn sources chelated Zn sources may be used instead because these sources have greater bioavailability of Zn. Chelated zinc may also reduce reactiveness with other components of the diet. A new chelated Zn source, zinc bis-glycinate, in which Zn is bound to two glycine molecules, was recently developed, but there is limited information about effects of this new chelated Zn source on digestibility and Zn retention in pigs. Therefore, an experiment was conducted to test the hypothesis that the relative bioavailability by weanling pigs of Zn in Zn bis-glycinate is greater than in Zn mono-glycinate and in ZnSO₄.