Objectives: We evaluated changes in the status of iron, zinc, and copper in non-anemic Peruvian infants who were receiving daily supplements of 10 mg of iron and 0.5 mg of copper with or without 10 mg of zinc from 6 to 18 mo of age. Methods: Overall, 251 infants were randomized to receive one of two daily supplements. Venous blood draws at 6, 12, and 18 mo of age were taken to characterize hemoglobin, plasma ferritin, zinc,and copper concentrations. The urinary excretion of zinc was also measured at each time point. Repeated measures analysis of variance was used to evaluate changes over time and by supplement type. Results: Both hemoglobin and copper concentrations increased significantly and plasma ferritin decreased from 6 to 12 mo of age (P < 0.05). Mean plasma zinc concentrations in the zinc treatment group were maintained over time, whereas zinc concentrations in the control group declined; differences by treatment were found at 12 and 18 mo of age (P < 0.05). Urinary zinc concentration was increased in the zinc group at 12 mo only. There was evidence that zinc treatment improved the hemoglobin level at 18 mo of age (P = 0.09). Compliance with supplementation was high, with 81% of the intended dose consumed over the 12-mo period. Conclusions: Daily mineral supplementation over the course of 1 y appears to be feasible and acceptable in this population. A combined supplement can improve the status of iron, zinc, and copper in infants at the same time. © 2013 Elsevier Inc.