The folate status and dietary folate intake of Taiwanese schoolchildren was investigated by analysis of both serum and red blood cell (RBC) folate levels and dietary folate intake in 1105 boys and 958 girls aged 6-13 years sampled from the Nutrition and Health Survey in Taiwan Elementary School Children 2001-2002 (NAHSIT Children 2001-2002). Mean serum folate levels were 18.3+/-8.8 nmol/L (8.1+/-3.9 ng/mL) in boys and 20.3+/-9.7 nmol/L (9.0+/-4.3 ng/mL) in girls. Mean RBC folate levels were 700+/-320 nmol/L (308+/-141 ng/mL) in boys and 751+/-347 nmol/L (331+/-153 ng/mL) in girls. The prevalence of serum folate deficiency was 1.4% in boys and girls, and the prevalence of marginal serum folate deficiency (7-14 nmol/L) was 31.1% in boys and 25.8% in girls. In addition, 8.5% of boys and 7.4% girls had RBC folate deficiency (RBC folate < 318 nmol/L), and 17% of children had marginal RBC folate deficiency (RBC folate of 318-454 nmol/L). Our results suggesting that Taiwanese schoolchildren have poor folate status especially during periods of rapid growth and development such as the transition from childhood to early adolescence (boys at age 12-12.9, girls at age 11-12.9). The average estimated folate intakes were 269+/-9 microg/d in boys and 259+/-9 microg/d in girls, and 42% of Taiwanese schoolchildren had a dietary folate intake below 2/3 of the RDA, indicating a poor dietary folate intake in this population. This study shows that the folate status of Taiwanese schoolchildren is currently inadequate and strategies are needed for improvement.