OBJECTIVE: Prenatal phthalate exposure is associated with adverse neurodevelopmental outcomes, yet data on impacts of early life exposure remains limited. We investigated phthalate and replacement plasticizer exposures from 2 weeks to 7 years of age in relation to brain anatomical attributes, using serial structural magnetic resonance imaging (sMRI). MATERIAL AND METHODS: Children were enrolled after birth into the UNC Baby Connectome Project, a longitudinal neuroimaging study. Urine samples (n=406) were collected at each visit and analyzed for 17 phthalate and replacement plasticizer metabolites. Among 157 children contributing 369 sMRIs, we calculated metabolite-specific average exposures across each individual's urine samples and used linear mixed models to estimate longitudinal associations of log transformed, specific gravity-adjusted average metabolite concentrations with gray (GMV) and white matter (WMV), and cortical volume (CV), thickness (CT), and surface area (CSA). We examined sex-specific differences in these associations. RESULTS: Higher average metabolite concentration was associated with lower GMV (MCPP: (-1.73 cm CONCLUSION: Early life phthalate/plasticizer exposure may differentially impact various brain region volumes in early childhood, with potential downstream consequences on functional development.