This study aimed to investigate effect of erythrocyte suspension (ES) transfusion on Cu, Zn, and Fe levels. It was conducted on 53 premature infants who were admitted to Hacettepe Hospital and received EST for first time. Blood samples were drawn before and 96 h after ES transfusion to determine Cu, Zn, and Fe levels in plasma and/or erythrocytes. The mean plasma Cu levels were 99 ± 3 μg/dl and 113 ± 3 μg/dl; Zn levels were 105 ± 2 μg/dl and 115 ± 23 μg/dl; mean plasma Fe level was 58.1 ± 19.4 and 75.2 ± 25.4 μg/dl and mean erythrocyte Fe level was 4182 ± 2314 μg/ml and 7009 ± 5228 μg/ml, before and after ES transfusion. The differences between before and after ES transfusion in Cu, Zn and Fe levels were significant. Correlation between plasma and erythrocyte Fe levels was significant both before and after ES transfusion. Though Fe overload is a major cause of morbidity/mortality after ES transfusion, alterations in trace elements should also be considered when transfusing blood to infants and children.