The effect of copper (Cu) deficiency on the reproduction and development in Xenopus laevis was evaluated, culminating in the development of a defined concentration-response relationship. Separate groups of four adult frog pairs were fed one of three diets for 28 d: (1) low-copper (−Cu); (2) copper supplemented (+Cu); and (3) ASTM standard beef liver and lung (BLL). Embryos collected from frogs administered the −Cu diet had markedly decreased egg masses and viability rates and an increased rate of necrosis when compared to the other dietary treatments. Malformations in −Cu larvae included maldevelopment of the heart, eye, craniofacial region, brain, and notochord. Larvae from adults administered the −Cu diet showed delayed abnormal hindlimb development, characterized as selective reductive deficiencies distal to the femur, with poor cartilaginous development. A U-shaped dose-response curve characteristic of nutritional essentiality was developed for Cu. Overall, these studies indicated that embryos produced from frogs administered a −Cu diet are substantially less viable than embryos from frogs administered a +Cu or copper-adequate (BLL) diet.