Infants born large-for-gestational age (LGA) are at risk for early childhood obesity. The aims of this study were to investigate factors associated with LGA status and their relationship to inflammatory biomarkers that have been implicated in the LGA infant at birth. Included were 364 mother-infant pairs enrolled as part of an ongoing longitudinal cohort study of infant birth weight being conducted at Boston Medical Center (BMC). LGA was defined as birth weight (BW) >/=90(th) percentile of the reference population at BMC (N=45). Appropriate-for-gestational age (AGA) was defined as BW<90(th) and >10(th) percentile (N=319). Cord blood IL-6, IL-8, TNF-alpha and RANTES levels were analyzed from a larger panel of immune biomarkers measured using multiplex immunoassay. Multivariate regression models were used to determine the associations between LGA status, maternal BMI and diabetes (DM), which included either gestational or type 2 diabetes (T2DM), and cord blood biomarkers, with adjustment for important demographic and clinical variables. Maternal pre-pregnancy BMI within the obesity range (>/=30 kg/m(2)), as well as DM, were each associated with increased risk of LGA (OR=2.64, 95%CI 1.31-6.20; OR=5.58, 95%CI 2.06-15.13, respectively). Among the 4 biomarkers, only RANTES (regulated on activation, normal T cell express and secreted upon uptake), which is a chemokine secreted by white adipose tissue, was significantly increased in LGA infants (beta-coefficient=0.37; 95% CI: 0.09, 0.65; P<0.01). This association remained essentially unchanged after adjustment for maternal DM and BMI (beta-coefficient=0.37; 95% CI: 0.08, 0.65; P=0.01). Ponderal index (PI=BWx100/length(3)) was also positively correlated with RANTES. Cord blood RANTES is selectively elevated with fetal macrosomia, independent of maternal factors. Further investigation of RANTES as a marker of LGA and future childhood health is warranted.