Less than 10% of pregnant women consume the AI of choline, a nutrient important for development. In animals, maternal choline supplementation (MCS) improves offspring behavior, but few studies have tested this in humans. In the present RCT, MCS caused higher placental and lower cord NR3C1 methylation, which is opposite the pattern associated with early adversity and offspring behavior problems in prior studies. We tested the independent associations between MCS and NR3C1 methylation and child behavior (BASC-III; n=21) at age 7, using adjusted linear regression. Mothers consumed 480 or 930 mg choline/d during the 3rd trimester. Cord blood and placentas were collected at delivery for methylation analysis, which focused on average and site-specific NR3C1 methylation. The 930 mg group reported fewer emotional self-control problems. Cord CpG 30-32 methylation was associated with fewer internalizing and anxiety problems. Results suggest that choline-induced changes in NR3C1 methylation may have functional consequences for child behavior.