Copper is an essential element that is a cofactor of many enzymes. Copper metabolism is disturbed in Wilsons disease, Menkes disease, Primary Biliary Cirrhosis and Indian childhood cirrhosis. Copper concentrations increase in acute phase reactions. They decrease in nephrosis, malabsorption and malnutrition. Copper levels are also useful to monitor patients specially preterm newborns on nutritional supplementation. Results of copper are often interpreted together with ceruloplasmin.