Although copper deficiency is a rare occurrence in the developed world, attention should be given to the proper supplementation of minerals to at-risk pediatric patients. This study presents 3 distinct cases of copper deficiency in hospitalized patients aged 14 months, 6 years, and 12 years. Two patients had short bowel syndrome, requiring prolonged parenteral nutrition or complex intravenous fluid supplementation. The third patient was severely malnourished. Copper deficiency manifested in all of our patients as either microcytic anemia or pancytopenia with myelodysplastic syndrome. Copper deficiency is an important diagnosis to be considered in patients with prematurity, parenteral nutrition dependency, malabsorption, and/or those with malnutrition. More studies are needed to establish appropriate amounts of copper supplementation to replenish copper stores in deficient patients.