Objective: The objective of this study was to determine the exposure of premature infants to lead from blood transfusions. Study design: Blood lead concentrations were determined for 19 very premature infants at the time of admission, at 4 weeks of life, and before and after transfusions and in the donor packed red blood cells of 79 transfusions. Results: The number of transfusions per patient was 4.2 ± 2.8 (mean ± SD) with 15.7 ± 1.9 mL/kg packed red blood cells for a lead dose of 1.56 ± 1.77 μg/dL. The total dose of lead from these transfusions over the 4-week period was 4.0 ± 2.8 μg/kg (range, 0.9-10.6 μg/kg). Increases in post-transfusion blood lead concentration were linear with doses higher than 1.5 μg/dL. Packed red blood cells with a blood lead concentration of ≥5 μg/dL resulted in an elevated post-transfusion blood lead concentration in some infants. Conclusions: The lead exposure to these infants through blood transfusion exceeds the acceptable daily intake values for lead and may result in unacceptably high post-transfusion blood lead concentrations. Use of packed red blood cells with lead concentrations <3.3 μg/dL is one cost-effective means to reduce exposure. (J Pediatr 2000;137:549-54)