The iron status of 28 children with phenylketonuria was assessed. Children were divided into one of three groups based on fasting plasma phenylalanine concentrations [< 605 μmol/L (n = 8); 605 to 726 μmol/L (n = 10), and ≥ 726 μmol/L (n = 10)]. No significant differences between the groups were observed with respect to age, height, energy, protein, tyrosine, or iron intakes. Iron intake ranged from 191% to 392% of the Recommended Dietary Allowance (RDA). Total iron binding capacity was significantly greater in children with plasma phenylalanine between 605 to 726 μmol/L than in children with plasma phenylalanine < 605 μmol/L. Additionally, as plasma phenylalanine concentrations in creased, concentrations of ferritin, hemoglobin, iron, MCV, MCH, and MCHC increased, Plasma phenylalanine concentrations correlated significantly with MCHC and ferritin. Plasma tyrosine concentrations did not correlate with plasma phenylalanine concentrations nor with any of the measured indices of iron status. Despite the high iron intake, several children had iron deficiency without anemia.