Background: US children consume folic acid from multiple sources. These sources may contribute differently to usual intakes above the age-specific tolerable upper intake level (UL) for folic acid and to folate and vitamin B-12 status. Objective: We estimated usual daily folic acid intakes above the UL and adjusted serum and red blood cell folate, serum vitamin B-12, homocysteine, and methylmalonic acid (MMA) concentrations in US children by age group and by the following 3 major folic acid intake sources: enriched cereal-grain products (ECGP), ready-to-eat cereals (RTE), and supplements containing folic acid (SUP). Design: We analyzed data in 4 groups of children aged 1-3, 4-8, 9-13, and 14-18 y from the National Health and Nutrition Examination Survey (NHANES), 2003-2006 (n = 7161). Results: A total of 19-48% of children consumed folic acid from ECGP only. Intakes above the UL varied from 0-0.1% of children who consumed ECGP only to 15-78% of children who consumed ECGP+RTE+SUP. In children aged 1-8 y, 99-100% of those who consumed >200 ug folic acid/d from supplements exceeded their UL. Although <0.5% of children had folate deficiency or low vitamin B-12 status, the consumption of RTE or SUP with folic acid was associated with higher mean folate and vitamin B-12 concentrations and, in some older children, with lower homocysteine and MMA concentrations. Conclusions: Our data suggest that the majority of US children consume more than one source of folic acid. Postfortification, the consumption of RTE or SUP increases usual daily intakes and blood concentrations of folate and vitamin B-12.