Objective Antenatal and early neonatal nutritional environment may influence later metabolic health. Infants of mothers with gestational diabetes mellitus (GDM) have higher risk for childhood obesity and metabolic syndrome (MetS). Leptin and adiponectin are known biomarkers for MetS and may guide interventions to reduce later obesity. We sought to examine the relationship between birthweight, early infancy feeding practices, and biomarkers for MetS in offspring of women with mild GDM. Study Design Secondary analysis of a prospective observational follow-up study on the offspring of women who participated in a multicenter randomized treatment trial on mild GDM. Children were evaluated by research coordinators and biospecimens collected at the age of 5 to 10. Plasma concentrations of leptin and adiponectin were compared between large for gestational age (LGA) and average birthweight (AGA) infants, and according to whether solid foods were introduced early (<6 months of age) or at the recommended age (≥6 months of age). Multivariable analysis adjusted for fetal sex, race/ethnicity, and maternal body mass index. Results Leptin and adiponectin were measured in 336 plasma samples. In bivariate analysis, compared with AGA children, LGA children had lower leptin (5.0 ng/mL [3.6-6.0] vs. 5.8 ng/mL [4.5 = 6.6], p = 0.01) and similar adiponectin (6.3 μg/mL [5.1-7.9] vs. 6.4 μg/mL [5.3-8.6], p = 0.49) concentrations. Maternal/child characteristics were similar between the early/delayed solid feeding groups. Leptin and adiponectin concentrations were similar in the early fed and delayed feeding groups (5.8 ng/mL [4.6-6.7] vs. 5.6 ng/mL [4.2-6.6], p = 0.50 and 6.4 μg/mL [5.4-8.1] vs. 6.4 μg/mL [5.1-8.8], p = 0.85, respectively). After controlling for covariates, children who were LGA and AGA at birth had similar leptin concentrations. Conclusion Birthweight and early infancy feeding practice are not associated with alterations in leptin and adiponectin in children of women with mild GDM. Key Points Adipocytokines are markers of metabolic status. Children of women with mild GDM may be at risk for MetS. Biomarkers similar in LGA and AGA groups. Biomarkers similar in early and delayed solid-fed groups. Nonhuman milk does not modify effect of feeding practice.