BACKGROUND AND AIM: There are limited studies quantifying the effects of paternal and maternal preconception environmental exposures on children’s health. The Preconception Environmental exposure And Childhood health Effects (PEACE) Study includes children (age 6-13 years) who were born to couples in the Environment and Reproductive Health (EARTH) Study and aims to determine the extent to which maternal and paternal preconception phthalate exposures are associated with neurobehavioral outcomes. METHODS: The PEACE study began in 2019 and is ongoing. A total of 478 eligible children (includes multiples) were born to 451 mothers who participated in the EARTH study (2005-2017). Study staff collected multiple maternal and paternal preconception urine samples before pregnancy and prenatal maternal urine samples during each trimester of pregnancy. We quantified 10 urinary phthalate metabolites in these samples. Children’s behavior, executive function, and reciprocal social behaviors are being assessed via parent-report using the Behavior Assessment System for Children-3 (BASC-3), Behavior Rating Inventory of Executive Function (BRIEF), and Social Responsiveness Scale-2 (SRS-2), respectively. Trained staff collected additional information about diet, sleep, physical activity, product use, and COVID-19 stress. RESULTS:As of March 2021, we enrolled 95 mothers, 57 fathers, and 120 children in the PEACE Study who completed visits either in person or virtually. Of children who completed the study, 64 (53%) were boys and 97 (81%) were White. Mean BASC-3 total behavior problem scores were 48.7 (SD: 7.6). Ten percent of children had scores indicative of being at-risk for behavioral problems (T-score60). Average BRIEF and SRS-2 scores were 48.2 (SD: 9.5) and 46.9 (SD:6.1), respectively. CONCLUSIONS:The PEACE Study will provide new information about the potential impact of parental preconception environmental chemical exposures on children’s health. In addition, the PEACE study will be able to leverage the rich data repository that includes parental chemical, built environment, and dietary exposures. KEYWORDS: Children's environmental health, Neurodevelopmental outcomes, Phthalates, Male, Chemical exposures, Endocrine disrupting chemicals, Female