Background: Leptin, ghrelin, and insulin are hormonal regulators of energy balance and, therefore, may be related to growth during infancy. Zinc is essential for growth, and its growth effects may be mediated through these hormones. Objective: We examined the effects of supplemental zinc on plasma leptin, ghrelin, and insulin concentrations among young children at risk of zinc deficiency and examined the relations between these hormones and physical growth. Design: Children (n = 142) aged 6-8 mo were randomly assigned to receive 3 mg Zn/d as a supplement, in a fortified food, or as a placebo for 6 mo. Relations between hormones and anthropometric z scores, body composition, and growth rates were examined at baseline and 3 and 6 mo after the start of the intervention. Results: No treatment group-related differences were found in plasma leptin, ghrelin, or glucose concentrations or in anthropometric z scores at 3 or 6 mo after the start of the zinc intervention. Neither plasma leptin nor ghrelin concentrations at baseline or 3 mo were predictive of subsequent changes in growth. However, changes in weight-for-age z scores over the two 3-mo time intervals were positively associated with subsequent leptin concentrations and inversely associated with subsequent plasma ghrelin concentrations. Conclusions: Supplemental zinc did not affect the children's growth, anthropometric indexes, or plasma hormone concentrations in this study population. Our results suggest that plasma leptin and ghrelin concentrations in later infancy are a consequence of previous weight changes rather than predictors of short-term growth. © 2007 American Society for Nutrition.